Hundreds of ambulance workers are calling for their chief executive to stay, fearing things will 'unravel' if he leaves.

More than 300 staff at the East of England Ambulance Service NHS Trust (EEAST) have signed a petition to Secretary of State for Health Jeremy Hunt, going over the heads of the EEAST board - as unions claim the board is not acting in its 'best interests' by moving to interview for a replacement chief executive.

The petition states that Dr Anthony Marsh, who was brought in as chief executive on a temporary basis in January 2014, running EEAST while remaining chief executive of the West Midlands Ambulance Service NHS Foundation Trust, had 'brought positive changes' to the trust but it was still in a 'very fragile state of recovery'.

The previous two chief executives had left the trust in a 'terrible mess', the petition added.

'We have made some progress, but there's a lot more to do, and we need Dr Marsh to stay and help us achieve that.

'We believe that without Dr Marsh things will again quickly start to unravel in our ambulance trust.'

But Fraer Stevenson, Unison branch secretary, said the petition sent a 'clear message' from staff and hoped board members would 'carefully consider' it.

An EEAST spokesman said: 'Anthony Marsh, who is also chief executive of the West Midlands Ambulance Service NHS Foundation Trust, was brought in to accelerate improvements in immediate service delivery and to build the foundations for long term sustainability for up to a two year period.

'As a result of a series of actions that he put in place when he took over in January 2014, services to patients and performance is significantly improved, although we recognise there is still much work for us to do.

'Now these service improvements are embedded, the time is right to recruit a new and permanent chief executive.

'In the meantime, Dr Marsh will continue as chief executive.'

It is understood applications have now closed and the service will soon start interviewing for a replacement.