A High Court judge who has been urged to overturn an “unlawful” decision to reduce services at a major hospital is set to announce his decision.

Campaigners plan to gather outside the Royal Courts of Justice in London before Mr Justice Silber rules on two legal challenges against cuts at Lewisham Hospital in south-east London.

Health secretary Jeremy Hunt told MPs in January that accident and emergency and maternity services at the hospital will be downgraded.

The London Borough of Lewisham and the Save Lewisham Hospital Campaign argue that the decision to cut some of the hospital’s services was “unlawful” and should be quashed.

Opponents say that if the decision is implemented it would result in “substantial” cuts to the services provided by Lewisham Healthcare Trust at the hospital.

Save Lewisham Hospital is a community based campaign group made up of and supported by patients, community groups, GPs, hospital doctors, nurses and other health professionals working in Lewisham.

Elisabeth Laing QC, for the council, told the judge at a recent hearing in London that Lewisham 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”.

The proposed changes are part of a wider shake-up of services in the capital after the financial collapse of neighbouring South London Healthcare Trust (SLHT), which went into administration after it started losing more than £1m a week.

Mr Hunt told MPs the changes would improve patient care in south London, saving up to 100 lives a year.

Ms Laing, describing the decision made in relation to Lewisham’s services as “unlawful”, said that - pending the court’s decision - the health secretary had undertaken not to implement the changes under challenge.

The judge heard argument on behalf of the health secretary that the decision made in relation to Lewisham was not unlawful.