The medical charity named Mace as construction manager last week. Bovis Lend Lease, Heery International and Interior Services Group had pitched for the role.
The extension, designed by American architect NBBJ, will be built on 24,000 m2 of greenfield land near the village of Hinxton. The masterplan for the scheme is currently with South Cambridgeshire council, which is considering whether to grant it outline planning permission. The trust is hoping to get the project on site in the new year.
If permission is granted, it will be the end of a lengthy struggle by Wellcome to get its extension built. A 40,000 m2 design by Sheppard Robson was submitted in 1999, but came to grief when the government decided it was too bulky.
The setback prompted the trust to look for another masterplanner. It shortlisted three architects for the scheme – NBBJ, RMJM and Sheppard Robson – at the end of last year.
A source at Wellcome said: "We are very sensitive about this project because it is so close to Hinxton, a very small village where residents are concerned about losing greenfield land."
The scheme includes laboratories, a data centre, an innovation centre, a car park and office space for commercial tenants.
Mace will be working with project manager Fuller Peiser.
The contract was won by a partnership of Gardiner & Theobald Construction Management and Kontor Skanska – a double whammy for the Swedish contractor as it is building the shell and core of the Foster and Partners design.
The joint venture will fit out the 14 floors initially due to be taken by Swiss Re in a contract thought to be worth £30m.
Work is due to start at the end of the year and be completed in early 2004.
As with the Wellcome extension, Bovis Lend Lease and Interior Services Group were in the running for the deal.