One of the UK's biggest PFI projects, the Ministry of Defence's £12bn Allenby/Connaught barrack renewal programme, has reached financial close more than four years after it was first tendered.

The 35-year PFI deal, which was let in early 2002, involves the servicing and refurbishment of buildings on 800 ha of army land around Salisbury Plain and in Aldershot.

Aspire Defence, a joint venture between Kellogg Brown Root and Carillion, will take forward the construction project, which is expected to last nine years and will provide facilities for about 18,000 military staff and civilians.

A spokesperson for Aspire Defence said work would start on site in the coming fortnight.

Architects working for the consortium include Scott Brownrigg, which masterplanned the schemes, and Broadway Malyan, which designed the working accommodation.

Consultant Cyril Sweett provided cost planning and management, whole-life planning and value management services. HSBC Infrastructure will be involved in funding the project.

A done deal: Scott Brownrigg’s design for some of the Allenby/Connaught facilities

A done deal: Scott Brownrigg’s design for some of the Allenby/Connaught facilities

The project will provide individual living quarters for servicemen. Altogether, new or refurbished accommodation is to be built for 11,000 personnel, including 145 modular-built 36-bed "junior rank single living accommodation" buildings.

A demonstration building has already been completed at Perham Down, and the three-storey blocks will be built in clusters. One building could be complete in about 16 weeks.

Three other teams bid for the original tender when it was launched in February 2002. They were: Bovis Lend Lease and Amey, Skanska and Interserve, and a team made up of Jarvis, Costain, Sodexho and Bouygues.

As part of the £8bn spend, £3.2bn has been earmarked for services over the 35-year life of the PFI, and construction will cost about £1.2bn.

A spokesman for Aspire Defence said the "highly complex" nature of the PFI contract had been at the heart of the delay in its reaching financial close. He said: "Aspire Defence really had to ensure that the contractual details were absolutely right especially as the contract will run for the full 35 years."

Carillion became involved in the project after its takeover earlier this year of Mowlem.