The three contracts form the final part of the Next Generation Estate Contracts programme to maintain and upgrade defence infrastructure.

Confirmation of the wins comes despite a legal challenge by losing bidder Interserve which forced the suspension of the contract award process.

Carillion and Amey were also confirmed in May as winners of the National Housing Prime contract and the Scotland and Northern Ireland Regional Prime contract.

The five contracts now secured by the joint venture have a total potential value of £4.5bn.

The latest Regional Prime Central contract is estimated by MoD to be worth £435m over the initial contract period of five years, which can be extended by a further five years.

This enlarged contract replaces the existing Regional Prime Contract Central, which is currently held by a Carillion joint venture with Amey and covers central and northern England and the whole of Wales, and the existing Regional Prime Contract East, as services in all these areas are being combined into one contract.

The joint venture will provide a wide range of hard facilities and asset management services at more than 150 sites together with the option to undertake capital works projects valued up to £3.93m.

The Carillion/Amey joint venture has also been awarded the South East and South West Regional Prime contracts that are estimated by MoD to be worth £258m and £265m, respectively, over the initial contract period of five years.

The South East contract will provide hard facilities and asset management services at 60 key sites, including Sandhurst, Horse Guards, HQ Land Andover and RAF Northolt.

The South West contract will provide hard facilities and asset management services at 40 key sites, including RNAS Yeovilton, DE&S Abbey Wood, RAF Lyneham and Britannia Naval College.

Mel Ewell, Amey’s Chief Executive, said: “Securing the Regional Prime contracts across the whole of UK is great news for the business and testament to the strength of the partnership with Carillion.

“This recent win allows us to add value by expanding the service, as well as sharing best practice and driving efficient ways of working across the defence estate.”

Carillion Chief Executive, Richard Howson, said: “We are delighted that our joint ventures have signed these three major contracts.

“This follows our recent success in winning the National Housing Prime contract and the Scotland and Northern Ireland Regional Prime contract and means that our joint ventures have won all five of the Next Generation Estate contracts for which we bid.

“We look forward to building on the strong relationship we have developed with Defence Infrastructure Organisation and to working closely with DIO to deliver further improvements to the quality and energy efficiency of the Defence estate across the whole of the UK.

“DIO set industry the challenge of providing added value to the military estate and by awarding us these five contracts providing UK wide coverage the offers we submitted have been recognised as generating demonstrable benefits in this regard, including the use of market leading customer feedback systems.”