The chairman of Surrey and Sussex Healthcare Trust, which runs Crawley and Horsham hospitals, is to retire in September.

George Gibson originally accepted the temporary chairmanship when the trust was formed in April, 1998, and has since twice agreed to extend his service to see through the merger between Crawley Hospital and East Surrey Hospital, Redhill.

Mr Gibson has not had an easy ride, with massive opposition to the trust decision to downgrade Crawley Hospital and move major services to Redhill. There have also been financial problems and huge waiting lists to overcome.

In a letter to Sir William Wells, chairman of the South East region NHS Executive, Mr Gibson said: "Now we have a Ministerial decision on the reconfiguration of services and we are in the process of appointing a new chief executive, I think it is timely for me to continue my retirement.

"I know that life has been difficult over the past two and a half years and I have striven to tackle issues in an effective a manner as possible.

"The achievement of agreement to the reconfiguration of services has been an important stage in the development of the trust and I am pleased to have contributed to this crucial phase."

Mr Gibson, former chief executive of Merton, Sutton and Wandsworth Health Authority, thanked his colleagues on the board, senior clinicians and the trust's staff for their support. Sir William said: "I have prevailed on George three times to remain with the difficult task of being chairman.

"I would like to thank him for all he has done for the NHS and for this part of the South East region in particular and for the huge contribution he has made to the work that has been undertaken on reconfiguration of services recently agreed by the Secretary of State."

The trust's new chief executive, Ken Cunningham, said Mr Gibson had seen the trust through a major period of change at a very challenging time.

His successor will be chosen from a regional list.

Sir William will put forward a proposal to Health Minister Gisela Stuart, who will appoint the new chairman.

A trust spokesman said this was a long process and until a decision was made the vice chairman, Vivien Hepworth, would take over.