Chief executive Iain McInnes is to join NHS Yorkshire and the Humber as programme director for primary and community care strategy. He had been at Scarborough for two years, and nine months ago negotiated the write-off of £20.7m historic debt in return for a deal to balance the books in the 2007-08 financial year.

Director of finance and deputy chief executive Sandy Hogg, who had been in post for a year, and non-executive director and audit committee chair Jason Brine have also stepped down.

A trust source said there was unhappiness within the board about the handling of the trust's core standards declaration to the Healthcare Commission, although there is no suggestion that the declaration was not accurate.

Unison official Ray Gray said: "It adds to the uncertainty of the last 12 months - we just need to know what sort of future the trust has."

The trust has had a difficult year, at one point threatening significant redundancies to reduce its debts. The future of maternity services and some acute services at Bridlington Hospital have been investigated by the independent reconfiguration panel, which is expected to report to the health secretary soon.

Christine Green, chief executive of Tameside Hospital foundation trust, will be chief executive until a permanent replacement is found.