The head of a struggling hospital trust is stepping down after 13 years in post.

Robert Lapraik, 56, is taking early retirement from the Royal West Sussex NHS Trust, which runs St Richard's Hospital in Chichester, at the end of the month.

The trust could be more than £36 million in the red by the end of March out of a budget of about £100 million.

When previous unpaid debts are added to this, the end result could be a loss of more than £50 million. It reported a deficit of more than £15 million last year.

St Richard's had an independent report of its finances prepared by auditor PriceWaterhouseCooper which said the crisis was so bad, the trust might not be able to pay its creditors without help.

It was also criticised by health minister Caroline Flint earlier this year for repeatedly failing to balance its books.

In spite of financial problems, the trust was given two stars out of three in the annual Government ratings.

Mr Lapraik, who earned between £105,000 and £110,000 a year after 13 years at the trust, said: "There is now an agreed recovery plan which is well under way.

"I have therefore decided that this is an appropriate time for me to move on. I am, however, immensely sad to be leaving St Richard's.

"I have been honoured and very proud to be chief executive of such an outstanding hospital."

Trust chairwoman Susan Pyper, who has only recently been appointed, said: "Robert must take credit for the hospital's many achievements and for its fine reputation."

Mr Lapraik joined the NHS in 1986 as a hospital general manager and after four years moved to Chichester as a district general manager, joining St Richard's in October 1992.

Trust director of operations and nursing Lyn Robertshaw will take over as acting chief executive until a replacement is appointed.

Mr Lapraik is the third Sussex hospital trust chief executive to leave this year.

Ken Cunningham stood down as chief executive of Surrey and Sussex Healthcare NHS Trust in February, just before the trust ended the financial year almost £30 million in the red.

There was outrage earlier this month when it emerged Mr Cunningham was given a payoff of up to £145,000.

There is also speculation former East Sussex Hospitals NHS Trust chief executive Annette Sergeant was given a package of up to £300,000.

The trust, which runs Eastbourne District General Hospital and the Conquest Hospital in St Leonards is also experiencing financial problems.

It is more than £3 million in the red and must save £17 million by the end of March.