A government challenge to overturn a High Court ban on planned cuts at Lewisham Hospital is to be heard today.
Health Secretary Jeremy Hunt suffered an embarrassing defeat when changes to emergency and maternity services were declared "unlawful" in July.
The government lost the case because the cuts were judged to be in breach of the National Health Services Act 2006.
The Health Secretary was attempting to deal with problems created by the financial collapse of neighbouring South London Healthcare NHS Trust, which went into administration after it started losing more than £1 million a week.
Rosa Curling, from law firm Leigh Day who represented the Save Lewisham Hospital campaign, says they are not worried about the government's continued fight to close some services down.
"We remain confident that the Court of Appeal will uphold Mr Justice Silber's decision" she said.
The Government is to appeal tomorrow against a High Court ruling over a decision to cut services at a hospital.
Health Secretary Jeremy Hunt suffered defeat when a High Court judge declared "unlawful" his move to downgrade A&E and maternity services at Lewisham Hospital in south-east London.
The judge ruled that Mr Hunt lacked power after being told the changes would mean local people having "to travel a long, long way further to get access to vital services".
The Government is now asking the Court of Appeal to rule Mr Justice Silber went wrong in law.
Campaigners marched the streets of Lewisham today, to say thank you to the community who supported their fight to stop the Government from shutting their hospital.
But questions are being raised about whether the celebrations are premature, after a High Court appeal against the decision to keep it open -- was launched by Health Secretary Jeremy Hunt.
In a single moment this morning, campaigners trying to save Lewisham Hospital from cuts to services knew their work had been worth it.
The High Court ruled the Health Secretary Jeremey Hunt had acted beyond his powers when he decided that the casualty and maternity units at Lewisham should be downgraded. The government will now appeal. Ria Chatterjea reports.
The judge gave the Health Secretary permission to appeal against his decision.
A Department of Health spokesman said:
"This judgment applies to one aspect of a package of changes which we believe are in the best long-term interests of patients and the public across south east London.
"As it stands, the South London Healthcare NHS Trust has been running at a loss of about £1 million a week - money that has to be diverted from frontline patient care.
So of course we are disappointed by this decision. We need to consider the judgment carefully, and have obtained permission to appeal.
"We expect to continue other elements of that package of changes, including the dissolution of the South London Healthcare NHS Trust, planned for October 1 - although there are a number of steps to go before that can take place."
Vicky Penner from Save Lewisham Campaign said the group are delighted the decision has validated their campaign.
Lewisham mayor Sir Steve Bullock said:
"Justice has been delivered. I am delighted for the thousands of people in Lewisham who fought so hard to have their voices heard and applaud all those who dared to hope and believe that together we could make a difference.
"Lewisham Hospital is well-managed, highly respected and financially solvent.
The special administrator should never have been allowed to make recommendations outside his remit, and the Secretary of State should never have adopted his recommendations, and this case should never have come to court."
Rosa Curling, a lawyer with solicitors' firm Leigh Day who is acting for the campaigners, said:
"This is a tremendous victory for all the people of Lewisham and for the thousands who have campaigned for this well-run, successful hospital to remain open.
"This mobilisation of the public in support of Lewisham Hospital has been extraordinary. Motivated by injustice, those who have campaigned for its survival have successfully shown that the decision taken by Jeremy Hunt to downgrade and close many of the hospital's services was wrong and unlawful.
"Real questions must now be asked about the decisions being taken by this Government in relation to healthcare.
Jeremy Hunt cut services at Lewisham Hospital because of financial difficulties faced by its neighbouring trust, South London Healthcare.
"These difficulties were caused by disastrous PFI contracts entered into by South London, which were costing #60 million a year to service.
The court found Jeremy Hunt had acted outside his powers by trying to make Lewisham pay for the financial problems of its neighbour.
"The Secretary of State cannot respond to the financial difficulties caused by the Department of Health's damaging PFI policy by simply imposing cuts on NHS services from above.
"This judgment should serve as a warning to the Government that, if they try to do this, local communities will fight back to ensure their healthcare services remain in place."
Health Secretary Jeremy Hunt has had his decision to reduce services at a major hospital declared unlawful and quashed by the High Court.
There was loud clapping in court as a judge ruled that Mr Hunt acted outside his powers when he announced to Parliament in January that casualty and maternity units at Lewisham Hospital in south-east London would be downgraded.
Mr Justice Silber said the Secretary of State had breached provisions of the National Health Services Act 2006.
The ruling was a victory for the London Borough of Lewisham and the Save Lewisham Hospital Campaign, a community-based campaign group made up of and supported by patients, community groups, GPs, hospital doctors, nurses and other health professionals.
Elisabeth Laing QC, for the council, told the judge at a recent hearing at London's High Court that Lewisham Hospital was a "very good hospital" and the range of health services provided there was "greatly valued by local people and by the council".
If the changes were made, it would mean local people "will have to travel a long, long way further to get access to vital services", said Ms Laing.
The proposed changes were part of a wider shake-up of services in the capital after the financial collapse of neighbouring South London Healthcare NHS Trust (SLHT), which went into administration after it started losing more than #1 million a week.
Mr Hunt told MPs the changes would improve patient care in south London, saving up to 100 lives a year, but gave an undertaking not to implement them pending today's legal challenge.
Dr Louise Irvine, a local GP and chair of the Save Lewisham Hospital campaign, said:
"This is an incredible day. We are delighted for every single person who has supported the campaign and those who will now continue to benefit from this extraordinary hospital.
The support from thousands of people in Lewisham is a very real demonstration of the Big Society.
David Cameron himself said there would be no 'top-down' approach to closures and we appreciate the court's decision, which should serve as a reminder to this Government not to forget their promises and not to underestimate those who they seek to represent."