Nicholas Drummond

Britain’s ageing fleet of Challenger 2 tanks needs urgent revitalisation. But given many other Land Warfare priorities does an upgrade programme make sense? Will we ever use tanks in combat again and does extending the life of Challenger 2 represent good use of a Defence limited budget? This article seeks to look at the importance of Challenger 2, the proposed Life Extension Programme (LEP) and whether we should consider alternative MBT options. 

Challenger 2 Iraq 2003


01 Origins
02 Cold War 2
03 Challenger 2 LEP programme status
04 Alternative MBT solutions
05 Towards the next generation
06 Summary

01 Origins

Britain’s Challenger MBT has been one of the most successful tanks to see UK service. It started life in 1976 when the Fighting Vehicles Research and Development Establishment (FVRDE) at Chobham revealed its revolutionary composite armour. This was attached to a heavily modified Chieftain Mk. 5 chassis, the FV4211, which over time evolved into the best protected NATO MBT.

The Chieftain MBT on which Challenger was based could trace its roots back to the Centurion tank of 1945, which was itself inspired by German Panther design of 1943. Centurion was among the most successful post-war tank designs with more than 4,300 exported to 17 different countries. It proved itself in British service in Korea, in Australian service in Vietnam, and later in Israeli service, during the Six Day War of 1967 and the Yom Kippur War of 1973. Despite being the first tank to mount a 120mm gun and having unprecedented levels of protection, Chieftain never received the acclaim of its predecessor. Its Leyland L60 engine developed only 750 bhp, which was insufficient for a 56 tonne platform, and it was unreliable. 

FV2011 Challenger prototype reveals Chobham armour for the first time 1976

Around the same time that Chobham armour was being developed, the former Shah of Iran paid Rolls-Royce to develop a V-12 diesel engine for the Chieftain to transform its mobility in a revised model, the Shir 1. When the armour and engine were offered to Iran in a single package, they became the basis for a new MBT called FV4030/3 or Shir 2. Iran ordered 1,225 and it would have entered service had it not been for the Iranian Revolution of 1979. After the order was cancelled, it is not clear how much of the development and manufacturing set-up costs were returned to Iran, but the British Army benefitted from the investment and a hot production line. In addition to a new chassis, new armour and new driveline, Challenger was fitted with Horstmann’s advanced hydropneumatic suspension, an improved L11A5 120mm rifled gun (which at that time possessed ammunition that made it superior to the German Army’s 120mm smoothbore gun) and an advanced thermal imaging observation and gunnery sight sight (TOGS). The first Challenger regiment achieved IOC in 1983 and the new tank established itself as a NATO benchmark.

Challenger can trace its roots back to the Centurion Universal tank of 1945, which was one of the most successful post-war MBT designs.
Chieftain Mk 5 MBT. Although it was the first tank to feature a 120mm gun and had excellent protection, it was underpowered and unreliable.

Although Challenger gave a good account of itself during Operation Desert Storm (Operation Granby) in 1991, it never fully lived-up to expectations. A lack of success in the prestigious Canadian Army Trophy (CAT) competition, suggested that its fire control system and sensors were inferior to those of both Leopard 2A4 and M1A1 Abrams. By this time, the dissolution of the Soviet Union had encouraged most NATO armies to reduce their armoured forces. Despite this and to its credit, the UK decided to invest in a revised version of Challenger. Vickers, now owned by BAE Systems, was commissioned to develop a new turret for the existing hull and Challenger 2 was born. By 1998, the British Army finally had an MBT that could be described as world class. During the UK’s second deployment to Iraq, between 2002 and 2011, Challenger 2 performed impeccably. No tank was lost to enemy action and many survived multiple direct RPG hits.

Given the British Army’s focus on counter-insurgency warfare from 2002 onwards, various defence planners were ready to write the obituary of the tank. Moreover, when the global financial crisis began to bite, the Army’s tank fleet became an easy target for budget cuts in the 2010 SDSR. At this time, the Royal Armoured Corps had 386 Challenger 2 MBTs in seven armoured regiments. Though we couldn’t quite bring ourselves to retire the whole fleet, numbers were cut to just 227. Plans to further upgrade Challenger 2, which began in 2006, were shelved. Thereafter, it was thought that Britain’s tank regiments would be left to quietly rust in peace.  

02 Cold War 2

In 2014, Russia annexed the Crimea. Relying on a mix of asymmetric and conventional tactics, an overwhelming superiority in artillery and the clever use of heavy armour allowed Russian forces to seize huge swathes of territory. The Ukrainian Army quickly re-learned the lesson that protected mobility is fundamental to tactical manoeuvre. It was not until the Ukrainians were able to muster a credible armoured force that they were able to counter-attack.

In case anyone doubted the enduring relevance of the main battle tank, Russia’s next move was to reveal the T-14 Armata MBT, T-15 heavy IFV, Kurganets 25 medium weight platform and the Boomerang 8×8. While it will take time before these vehicles are deployed in large numbers, Russia is steadily upgrading its existing fleet of 11,000 T-72s while increasing the number of T-90s it has to more than 500.   

T-72 MBT
While Russia’s new T-14 Armata is impressive, it has yet to be produced in large numbers. Meanwhile, it is upgrading its fleet of 10,000 T-72s.

Russia’s comprehensive renewal of its Land Warfare capabilities has reignited previous cold war tensions and a new Cold War has begun. As a consequence, many NATO armies, including the US Army, Bundeswehr and French Armée de Terre have begun to upgrade their tanks. The M1A2C Abrams (previously SEP V3) is already in series production, while a further revised model the M1A2D (previously SEP V4) is under development. Germany is upgrading stored Leopard 2A4’s to the latest A7 standard and intends to field a larger fleet of 320 MBTs. France will improve 200 of its Leclerc MBTs. More important, the merger of Krauss Maffei Wegmann and Nexter has seen work begin on the next generation of Main Ground Combat System (MGCS).

Any notion that armour is irrelevant has been be dispelled by the fact that so many legacy tanks remain in service across the world. Estimates suggest that there are as many as 53,000 tanks in active service with a further 20,000 held in reserve storage. The vast majority of these are older models, but as the Russians say: any tank is better than no tank. Meanwhile, Russia seems intent on re-integrating former Soviet satellite states; China is building its forces beyond any territorial defence needs; Iran is a persistent threat to Saudi Arabia and Israel; and the North Korean situation is far from settled. In other words, the world is increasingly volatile and unstable. NATO undoubtedly needs to retain potent ground forces. While Cyber / EW warfare and asymmetric tactics offer new options, recent and ongoing conflicts suggest that the distinction between war and peace has become less well delineated. This requires NATO to be vigilant and prepared. Today, we go to war with the Army we have, not the Army we would ideally like. 

03 Challenger 2 LEP programme status

More than a decade after it was first envisaged, Britain’s Challenger 2 Life Extension Programme (LEP) commenced in 2016. What remains of the original fleet is now in such a poor state of repair that we would struggle to deploy a brigade let alone a full war-fighting division. Realising that tanks remain vital to support armoured infantry in high-end conventional warfare against peer enemies, the programme has rightly assumed a higher priority. 

Two bidders were down-selected for a two-year assessment phase: Rheinmetall and General Dynamics / BAE Systems. The winning bidder is expected to be announced in Mid-2019. Interestingly, a 120mm smoothbore has been added to the scope of the RFQ. This makes it an upgrade programme rather than simply an obsolescence management exercise. The addition of a 120mm smoothbore will give UK tank regiments the ability to fire all NATO 120mm smoothbore ammunition natures. With commonality and interoperability becoming NATO buzzwords, the adoption of such a weapon can only be a good thing. Rheinmetall’s current 120mm smoothbore gun, the L/55 Mk II, remains highly capable. Its DM53 / DM63 APFSDS kinetic penetrator is able to punch through 750 mm of RHA steel at a range of 2,000 meters, exceeding the penetration effect of Challenger’s CHARM 3 round, while the German company also offers a devastating new programmable air burst munition, the DM11.

2016-08-11_Rheinmetall Challenger 2 LEP
Rheinmetall’s Challenger 2 LEP proposal. (Image: RLS UK)

A major question that LEP bidders must answer is how a 120mm smoothbore can best be incorporated into Challenger 2? This was something considered in 2006, during the previous Challenger 2 CLIP initiative that was cancelled. Given that the German gun uses larger one-piece ammunition versus Challenger 2’s two-piece system, there is insufficient space to store 120mm smoothbore rounds in Challenger’s existing turret bustle. To ensure that Challenger 2 can carry sufficient ammunition, the rear section of the existing turret will need to be re-engineered or the entire turret will need to be swapped for a new one. 

Challenger 2 CLIP programme of 2006 considered how a 120mm smoothbore could be mounted in the Challenger turret. This work may be revisited.

At the International Armoured Vehicles (IAV) conference in January 2019, Rheinmetall revealed its Challenger 2 LEP proposal. This has a brand new turret with the L/55 120mm smoothbore gun. Although externally the new turret looks similar to Challenger 2’s existing one, Rheinmetall has taken an existing Leopard 2 turret and comprehensively re-engineered it. Ammunition storage is in an enlarged turret bustle and below the turret ring in sealed compartments. Rheinmetall plans to use the same sensors, fire control system and BMC4I solution as Ajax. While Rheinmetall’s Challenger 3  certainly looks impressive, it is likely to be much more expensive per MBT than the changes envisaged by the scope of original Life Extension Programme.

Rheinmetall proposal 

Given that Rheinmetall has acquired BAE Systems Land Systems business unit, it isn’t clear how this will impact the General Dynamics / BAE Systems consortium and their Challenger 2 LEP proposal. GDLSUK was expected to offer a redesigned version of the existing Challenger turret with a similar sensor and FCS package. There are also rumours of a mysterious third option. This could be Nexter’s Leclerc turret mounted on the existing Challenger 2 hull. This is noteworthy because it features not only a 120mm smoothbore, but also an extremely robust autoloader. KNDS showed this turret mounted on a Leopard 2 chassis at the 2018 Eurosatory Defence Exhibition. As well as helping to isolate the crew from ammunition storage in the event of a fire, it also has the potential to reduce platform weight by around 10 tonnes. 

The Leclerc MBT has a crew of three instead of four: Commander, Gunner and Driver. With an autoloader, it doesn’t need a fourth crew member to act as Loader. From a UK perspective, this is a disadvantage as having more crew members makes heavy manual tasks, like changing tracks, easier. Since most new tank designs have crews of three instead of four, we may need to accept that a reduction in crew size is inevitable. In the meantime, Challenger 2 seems likely to continue with four. 

KNDS Euro MBT concept with Leclerc 2-person turret with autoloader mounted on a Leopard 2A7 chassis. At 60 tonnes, it achieves a useful weight saving versus Challenger 2. (Image: KNDS)

The UK MoD has released few concrete details about Challenger 2 LEP. What we can say is that the platform will become UK GVA compliant so that it can integrate the Bowman tactical communication system now and later the new LETacCIS system. It has also been announced that Challenger will get an APS package. We know that the drivetrain will also be upgraded via a separate initiative, the Heavy Armour Automotive Improvement Programme (HAAIP), but, not whether this will include the EuroPowerPack with MTU’s 1,650 PS (1,214 kW) MT883 V-12 diesel engine. It would easily fit into Challenger’s engine bay and likely be coupled to a Renk HSWL 354 transmission . 

If Challenger is fitted with the Leopard 2’s driveline, turret and gun, it will be a Leopard in all but name. However, Leopard’s off-road mobility, because of its lower overall weight, is superior. Another significant factor is Leopard 2’s price. Rheinmetall’s Challenger 3 is estimated to cost around £12 million, but the price of a new build Leopard 2A7 is €8-€9 million. So we might be better off just buying Leopard 2.

Meanwhile, Nexter / KMW and Rheinmetall are both working on new MBT designs. Rheinmetall could have a new tank ready by 2027. In which case, why not retire Challenger 2 now and gap the capability until the new MBT is ready?

Artist’s impression of Rheinmetall Next Generation MBT.  Lighter in weight but with greater protection, its 3-person crew are located in a central armoured cocoon. The unmanned turret has the Company’s new 130mm smoothbore gun with an autoloader. (Image: Marcel Adam)

An upgraded Challenger 2 ought to have entered service in 2016. Under current plans, it is unlikely to do so before 2023. The original cost was meant to be about £2 million per tank. After 2015, it increased to £774 million, or £3.4 per Challenger 2 MBT. If costs rise above this level, it will reduce the total number we can afford.  It has already been suggested that the Army will lose another tank regiment, meaning that we will only have 168 platforms, but if the price is £12 million each and the total budget needs to increase to £2 billion, we could cut numbers to 132 – this less tanks than Cyprus or Switzerland.  If Challenger 2 remains in service from 2023 to 2035 (instead of from 2016 to 2035) it begs the question: is it actually still worth upgrading it at all? And, if not, what should we do instead?

The bottom line is that the British Army would not be able to take-on a peer enemy without having a credible main battle tank. We need an upgraded MBT as soon as possible. If the threats we face were not existential, we could risk retiring Challenger 2 while a new MBT is developed. Regrettably, a next generation MBT is unlikely to be ready before 2030. To have a further “capability holiday” with no MBT between now and then would an unacceptable operational risk. This means we could be forced to spend money on a solution that’s likely to have a short shelf-life or we will need to keep it in service long after other armies have replaced their MBTs. 

If we are paying more for less, it is important to point-out that this is not the fault of the Army or the MoD, but due to a short-sighted political decision to cut the Defence budget in 2010. The important question we now need to ask is: can we acquire an acceptable number of credible MBTs at a lower price than the cost of the Challenger 2 LEP?

04 Alternative MBT solutions

The US Army has approximately 3,500 M1A1 Abrams sitting in a Californian desert. It should be possible to acquire 230 of these for around $1.5-$2 million each and upgrade them to the latest build standard. Adding a new fire control system is likely to cost $2-$3 million per tank, so we could acquire a substitute MBT at a cost of $3.5-$5.0 million each (or $1 billion in total). 

Buying the US Army’s M1 Abrams tank would have two disadvantages. One is the cost and complexity of bringing a major new vehicle platform into UK service with all of the related DLOD requirements; the other is that it has a gas turbine engine. Although the engine is thirsty, it can use a variety of fuels. US Army M1A2Cs are now fitted with an auxiliary power unit which reduces fuel consumption when the tank is stationary. As an alternative, General Dynamics has already looked at integrating the MTU EuroPowerPack fitted to Leopard 2, so this could be another option, although it would increase unit price. Again, the choice boils down down to cost. One important benefit of acquiring the Abrams is that it would give us improved interoperability with the US Army. Above all, Abrams is an excellent tank that has performed exceptionally well during recent deployments. Its basic design has stood the test of time better than Challenger 2 because the original design recognised that it would need to be upgraded over the course of its lifecycle. Furthermore, it may well be the least expensive means of acquiring an MBT with a 120mm smoothbore. It is something we need to look at again. 

M1A1 Abrams MBT of the US Army. More than 8,000 have been manufactured with a vast number held in storage.

It seems probable that the US Army will acquire a significant quantity of M1A2Ds. Tagging a G2G order for 230 on the back of a large US order, could be more efficient, faster and less expensive than retaining Challenger 2. At the very least, a serious evaluation would enable us to negotiate better price from Challenger 2 LEP bidders.  

A second option,  as noted above, could be to purchase new-build Leopard 2A7s. Like the M1A2 Abrams, this is an excellent design that has been proven in combat. There is a hot   production line. Leopard 2 would give us commonality with Germany as well as many other NATO Alliance members. It already has the L/55 120mm smoothbore gun and state-of-the-art Fire Control System. It would truly be a viable off-the-shelf system that could be deployed immediately if need be.

One important distinction between the M1A2C/ D Abrams and Leopard 2A7 is that the latter uses an L/55 calibre gun whereas the American M1 uses a L/44 calibre smoothbore, the M256. In order to compensate for the lack of velocity from using a shorter barrel, the US Army uses the M829A3 depleted uranium kinetic penetrator, while Germany uses the DM53 A1 and newer DM63 APFSDS penetrators with tungsten cores. Both guns provide similar performance and can fire each other’s ammunition.

If we wanted to be really creative, we might wish to have a look at the Korean K2 Black Panther or the Japanese Type 10, both of which have the same three-person configuration as the French Leclerc. Neither has been combat tested and the only real reason to consider them is if they offer a price advantage. Since they are both appear to be as expensive as the Leopard 2, they can probably be discounted. 

Israeli Army Merkava Mk 4 MBT.

The Israeli Merkava Mk IV is another interesting choice. After the M1 Abrams and Russian T-72, it is the most combat tested MBT in service today. It mounts an L/44 calibre 120mm smoothbore gun and offers high levels of survivability. Uniquely among modern MBTs, the Merkava’s engine is mounted in the front of the vehicle, offering increased protection and allowing the crew to escape through the rear of vehicle if it is hit. The rear crew compartment also allows the tank to be converted into a heavy Infantry Fighting Vehicle, the Namer. One key insight from the Ukraine conflict is that armoured infantry units need the same level of protection as tank crews, making Merkava / Namer an attractive option. Not much is known about current Merkava pricing, but if it were close to that of the Abrams, it would be worth evaluating. 

Ultimately, the Challenger 2 Life Extension Programme is about minimising cost so that the Army has the cheapest possible main battle tank able to provide a credible capability until a new design can be fielded. An upgraded Challenger 2 can be expected to have life expectancy of 15-20 years. Assuming it enters service in 2023, it would remain in service until 2040. 

05 Towards the next generation

Now and in the future, armies will continue to rely on two basic types of armoured vehicle. One to provide protected mobility for transporting troops safely around the battlefield; the second to provide mobile firepower for neutralising enemy vehicles and to support infantry. Tracked or wheeled, medium or heavy, in high or low intensity conflicts, across open country and in urban environments, armoured vehicles can be expected to remain relevant to a wide range of roles and mission types.

Traditionally, protection and firepower have been prioritised above mobility. With a greater need for expeditionary capabilities, we should expect to see the iron triangle rebalanced in favour of mobility. As well as the three traditional elements, three new elements have assumed a much greater importance: sustainability, which is the logistical footprint and and ease of supportability; connectivity, which is is the ability to collect data and share it with other vehicles / formations to build an accurate real time picture of the battlefield, including friendly and enemy force dispositions; and adaptability, which is ease with which a platform can be reconfigured for different missions.  

Modern armoured warfare.013
The “Iron Triangle” has evolved into a Capability Matrix that now includes Sustainability, Connectivity and Adaptability.

Under the guidance of various military customers, defence firms in North America and Europe are working on future NATO tank concepts. By 2020, we should begin to see a number of prototypes emerge. Common innovation themes include: central crew citadels (where the crew sit within a protected cocoon for increased survivability); remote-control turrets with autoloaders that separate the crew from ammunition stowage; active protection systems (APS) that neutralise kinetic threats as well as chemical-effect anti-tank warheads; fully-networked battlefield management systems that fuse voice and data communications; manned and unmanned systems; increased automation and artificial intelligence to reduce cognitive burden; advanced sensors to support 24/7 missions; integral UAV launch and recovery; hybrid-electric drivetrains; and wheels should progressively replace tracks. 

Given the burgeoning cost of AFVs, and the need for armoured infantry to enjoy the same degree of protection as their tank crew comrades, it is likely that dual platforms for MBT and IFV will be developed. The Israeli Merkava and Namer are good examples of this trend and complement each other perfectly.

The other requirement is for heavy armour to become more deployable. This means tanks need to shed weight, hence the move to smaller remote turrets with autoloaders, which typically shave-off around 8-10 tonnes. Another means of lowering weight is to reduce the protected volume of the vehicle, which is a factor driving the development of smaller unmanned ground vehicles (UGVs). 

Future MBTs and IFVs are likely to weigh 50 tonnes, possibly more with mission-configurable appliqué armour. This suggests that they will be tracked, unless 10×10 or 12×12 wheeled configurations prove to be viable. With fully electric drives and hub motors in every wheel, there is every possibility that future wheeled vehicles will match tracked vehicles even in the most extreme off-road conditions. Unfortunately, we need battery technology to catch-up so that electrically-powered heavy armour has an acceptable combat radius. 

For the foreseeable future, heavy armoured vehicles are expected to remain tracked and to be powered by legacy diesel engines. This means we will need wheeled medium weight armour to complement them, such as 8×8 or 6×6 platforms like Stryker, Boxer, or Griffon. To be easily deployable, medium armour vehicles need to weigh less than 40 tonnes (or less than 37 tonnes if we want them to be air-transportable in an A400M). So the new armoured paradigm seems to imply a matrix of four primary combat vehicles: heavy MBT and heavy IFV; medium gun system and medium infantry carrier. Below them, there will be a light protected vehicle category. This class will be comprised of 4×4 light protected mobility or command and liaison vehicles, such as JLTV, Bushmaster and Foxhound. 

Modern armoured warfare.005Ultimately, heavy armour takes longer to deploy, is less autonomous and has a larger logistical footprint; but it has the firepower and protection needed for resilience. Conversely, medium armour deploys rapidly, is more independent and has lower logistical footprint; but lacks the firepower and protection needed for sustained high-end peer-to-peer warfare. 

Another important factor is cost. The more affordable a vehicle is, the more we can buy. It is important to remember that Allied superiority of Sherman tank numbers in Normandy1944 overcame the quality of Axis Tiger and Panther tanks. Relative to the Tiger, the Sherman tank was simpler, easier and less expensive to produce. We triumphed because Germany ran out of tanks before we did.  Today, modern MBTs have become so sophisticated and costly, we lack critical mass in terms of absolute numbers.  

Any or all of the above assumptions could easily be challenged by new weapon technology. Over the last decade, Active Protection Systems have restored the primacy of heavy armour. But it won’t be long before new anti-tank missiles appear that can defeat APS.  A new system receiving much attention in British circles is Electro-Magnetic Pulse (EMP) munitions. If they work as we hope they will, they will destroy all electrical systems within a combat vehicle, effectively turning it into a redundant hunk of metal. 

Although new AFV concepts will debut over the next five years, it is likely to be a decade before any radically new combat vehicle enters service. Armies tend to be conservative, which makes them evolutionary in their approach rather than revolutionary. System reliability trumps innovation when lives are at risk. We will test new concepts comprehensively before committing to fielding them at scale. 

 06 Summary

As the British Army begins to envision what AFVs will be required beyond 2030, it still needs dependable heavy and medium weight armoured vehicles now. Ajax and Boxer will enter service by 2023. But the Armoured Infantry brigades need upgraded MBTs too, which is why the Challenger 2 LEP is an essential programme. In making a recommendation about next steps, there are three MBT priorities:

  • The need to upgrade all 227 Challenger 2 MBTs and commit to fielding at least three regular MBT regiments
  • The need to mount a 120mm smoothbore to ensure ammunition commonality and interoperability with our allies
  • The need to reduce system weight and logistical footprint to increase system mobility

Of these above requirements, the most difficult to achieve is weight reduction. Even so Challenger 2 can be expected to remain a formidable system. 

AbramsIf we can acquire a basic second-hand M1A1 Abrams with a 120 mm smoothbore gun; upgrade them to the latest M1A2D standard (so that it is essentially a new tank) and, at a cost that is less than that of upgrading Challenger 2, then we should seriously consider it. If Challenger 2 LEP can be achieved at a cost that is acceptable, then it may be the most pragmatic solution. Perhaps the acid test is timeline. And, who knows, there may be life in the old dog yet!