Two ageing hospitals are to get a £1.2bn revamp to create the UK's biggest hospital, the government has confirmed after weeks of uncertainty.
The two ageing hospitals are to be redeveloped
The Royal London and Bart's hospitals in east London are to be redeveloped in the UK's biggest PFI hospital scheme.
Fears it would be scrapped after a review was ordered prompted 1,000 doctors to write in protest.
Critics said the delay had added an extra £35m to the cost, but the health secretary said £650m had been saved.
When she ordered the review in December, Patricia Hewitt told MPs the project's cost had doubled in four years, while cardiac care waiting lists had fallen.
But, in an open letter to the prime minister, 1,000 doctors said the project was vital to the health of people in east London.
On Wednesday, the health secretary defended the delay saying: "I had to be absolutely certain that we were getting the right facilities for this part of London and that we were getting the best possible value for money for patients before we committed over £1bn in capital for the next 35 years."
She said the revised programme had everything that had always been planned, but required less public money.
Under the revised plans, one floor at Bart's and two at the Royal London will not be fitted out until it is known whether east London's population increases enough to need them.
And the Barts and The London NHS Trust has also agreed to wait before refurbishing existing buildings.
But the redevelopment will create the UK's biggest hospital, with 1,248 beds, and Europe's largest accident and emergency department.
The historic Georgian buildings of Bart's - the UK's oldest hospital - will be refurbished alongside a new building which will house the cancer and cardiac centre.
The new hospital at The Royal London will have two glass towers, one with a helipad for the London's Helicopter Emergency Medical Service.
The PFI plans envisage two hospitals having 1,248 beds - 186 more than they have currently, with many patients in single rooms with en suite facilities, and the rest in four-bed bays.
Trust chief executive Paul White said: "After decades of under investment, the people of east London and our 8,000 staff can now look forward to the world-class new hospitals they deserve."
Wendy Mead, from the Save Barts Campaign, criticised the delay adding: "It all looks a bit like a face-saving exercise from the Department of Health who were hoping to close Barts, and they have not managed to do it."
The St Bartholomew's and the Royal London Charitable Foundation will make a grant to allow the trust to buy major state-of-the-art medical equipment.
Construction of the new hospitals will begin in the coming weeks and the new facilities are expected to be fully complete by 2016.