The planned 290,000 sq ft hospital building, designed by Hawkins\Brown Architects and Bouygues-owned developer Linkcity, is to be rebid after the Trust and pre-construction services agreement contractor Bouygues agreed to part company on amicable terms.

The Trust is now asking interested firms to register before inviting tenders in March for the integrated £250m main shell and fit-out contract.

Previously Bouygues UK was in line to just deliver the shell and core for the new hospital extension.

Trust procurement chiefs said the change of scope required a fresh procurement competition. The Trust now hopes to start construction by the end of next year.

The Trust intends to utilise a hybrid design & build delivery route for the Evelina Expansion Programme. This will include fixing the shell and core through a Single Stage D&B while the fit-out works will utilise a two-stage D&B approach.

The proposed 12-storey building, which will be located on a triangular sited behind Lambeth Palace on the opposite side of the Thames to the Houses of Parliament, will be joined to the existing, award-winning children’s hospital which opened in 2005.

New extension will house 100 beds, operating theatres and spaces for patients to relax, including a roof terrace.

As capital project advisors for the Evelina Expansion Programme, Mace is running the market engagement briefing. Documents are available from the procurement website. Questionnaires need to completed by 14 January.

In advance of the main contractor works several pre-commencements works will be carried out by the Trust, including, the demolition of the existing buildings.

Professor Ian Abbs, Chief Executive of Guy’s and St Thomas’ NHS Foundation Trust, said: “Our ambitious plan to expand Evelina London will make it one of the world’s leading children’s hospitals, and enable us to provide exceptional care to many more children and young people.

“This is just the beginning of an exciting journey for us, and we will continue to put patients and families at the heart of what we do.”

The bigger and better children’s hospital, which will open in 2027.