An effort by the British Army to extend the life of its Challenger 2 main battle tanks out to 2035 is due to move into a new gear next month as some of the world's top armored-vehicle suppliers submit bids to secure work under the program's assessment phase.

Up to 227 tanks are to undergo a life extension program aimed primarily at addressing obsolescence issues in the turret, but it's possible some limited capability enhancements also will be added.

Studies into the art of the possible on upgrading lethality, survivability, power pack and other systems will be part of the upcoming assessment phase contracts.

The Challenger 2 Life Extension Programme is one of several armored-vehicle programs the British Army has in its sights, budgets permitting.

The purchase of an 8x8 wheeled mechanized infantry vehicle (MIV) is expected to formally get underway in the next few weeks and is the army's top new program priority.

General Dynamics UK is already working on a £3.5 billion ($5.1 billion) deal to produce 589 tracked Ajax-family scout vehicles, and Lockheed Martin UK is developing a Warrior infantry fighting vehicle sustainment program ahead of an expected production contract.

A protected-mobility vehicle program is also in the works.

"The British Army's existing plans suggest that in terms of armored-vehicle modernization Challenger is their lowest priority. That's not to say there isn't money for it but they are quite clear that after Scout they have two priorities, one is Warrior and the other is bringing forward the MIV," said Ben Barry, the senior land warfare analyst at the International Institute of Strategic Studies think tank in London.

"What is clear is that all the messages from the army suggest they have had to make hard choices because a lot more modernization would be going into Challenger 2 if they had the funds," he said.

Work on Challenger 2 modernization has been underway for several years, but the decision in the 2015 strategic defense and security review to push back the 2025 out-of-service date by 10 years and mounting issues with aging systems have finally helped advance the program.

The MoD hopes to name the winning assessment phase teams around October and select a winning submission in 2019.

BAE Systems, CMI Defence, General Dynamics, Krauss Maffei Wegmann, Rheinmetall and Ruag have all previously expressed an interest in the program.

With bids due to the Ministry of Defence by July 14, the actual lineup of contenders for the award of two 24-month competitive assessment phase deals started to become clearer June 3 when two of the world's leading vendors of land systems declared they would mount a joint bid.

BAE and General Dynamics UK announced they were partnering in an industry consortium which also includes Leonardo-Finmeccanica (formerly Selex ES), Moog, Safran Electronics, and General Dynamic Mission Systems.

BAE, the design authority on the Challenger 2, will lead the bid with GDUK, sharing the integration and systems work with its erstwhile rival as well as physically undertaking the life extension work at a new facility it is building at Merther Tydfil, South Wales, to assemble the Ajax.

Kevin Connell, the vice president of land systems at GDUK, said there is sufficient capacity at the factory to run the two programs in parallel.

The GDUK executive said the partners hoped to find logistics, training, electronic-architecture and other synergies between Ajax and the main battle tank update to help drive affordability.

Lockheed Martin UK, also confirmed it was bidding, but as of late last week it was keeping its potential suppliers under wraps.

"Given our successful involvement in the Ajax program as turret provider and Warrior capability sustainment program as prime contractor, we are in a strong position to compete for the project with a proposal that demonstrates strong UK industrial participation involving a wide-ranging supply base. We plan to announce further details of our proposal in due course," said a spokeswoman for Lockheed Martin UK.

The UK arm of Lockheed Martin opened a new facility at Ampthill, north of London, where it plans to undertake the Ajax and Warrior turret integration and test work, which has propelled it into a leading position in the UK armored-vehicles market alongside BAE and GDUK.

Company officials say the Challenger 2 program would be well aligned with their existing work.

Like GDUK, the company hopes to benefit from synergies on exiting vehicle programs.

Swiss company Ruag Defence also confirmed it would be bidding as a prime contractor.

"We are supported by a group of various sized UK based industrial partners, and if successful, intend to carry out much of the work in the North of England," said a company spokesman.

Belgian contender CMIDefence is expected to announce July 14 it is tying up partnering with British vehicle engineering experts Ricardo UK to bid for the Challenger requirement.

Ricardo is perhaps best known recently on the defense front for its helped in developing and building the General Dynamics Foxhound light protected vehicle for the British Army.