An NHS Trust which is losing £1 million a week has become the first in the country to be put under the control of a special administrator, the Department of Health announced on Thursday.
South London Healthcare NHS Trust has been put on the "unsustainable providers regime" and an administrator has been tasked with putting it on a viable footing, a deparment spokesman said.
The trust, which runs three hospitals, has been criticised over standards of care and has run up deficits of more than £150 million over the past three years.
The trust runs Queen Mary's in Sidcup, the Queen Elizabeth in Woolwich and the Princess Royal University Hospital in Bromley.
Despite efforts to improve its financial performance, it is still thought to be on track to lose between £30 and £75 million a year for the next five years.
Matthew Kershaw, who works as the national director for provider delivery at the DH, was appointed as special administrator.
He will take over the board and recommend measures to the Health Secretary to put the trust's finances on a sustainable basis.
Mr Lansley said: "Past efforts have not succeeded in putting the South London Healthcare Trust on a sustainable path.
"This will be a big challenge and my key objective for all NHS Trusts is to ensure they deliver high-quality services to patients that are clinically and financially sustainable for the long term.
"I am confident that with the regime I am enacting today in place, and working extensively with clinicians, health service leaders, patients and local people, Matthew will have the tools and framework in place to find a long-term satisfactory solution for the people of south east London."
Mr Kershaw added: "My priority is to work with staff, patients, the public and all those involved in healthcare services in the south east London area to maintain high quality, effective services during the running of the Unsustainable Provider Regime.
"This means developing recommendations that ensure that people in south east London can access high quality, safe, and financially sustainable NHS services for the long-term.
"Together we will need to think differently, be bold and accept that change needs to happen. The status quo is not sustainable."
Unison called for the Government to clear the debt of the Trust.
Christina McAnea, head of health at the union, said: "Local people and health workers will be really worried about the future of the vital services they rely on or work hard to provide.
"If the Government is happy to bail out the banks, why can't it clear the massive PFI debt that is dragging the trust into financial difficulties? The future looks grim for healthcare and jobs but these services are too vital to be allowed to fail."