Care minister and North Norfolk MP Norman Lamb has called on the board of the East of England Ambulance Service Trust (EEAST) to take its time over appointing a new chief executive.

Current head Anthony Marsh will step down next year when a replacement is found, the trust confirmed on Tuesday night.

Mr Marsh is 11 months into a two-year contract and has been splitting his time between the East of England and West Midlands trusts where he is also chief executive.

Mr Lamb said: 'I want to make sure the board doesn't go for a quick option.'

He added he was 'very disappointed' that Mr Marsh had decided to leave the £232,000 a year post early.

In a message to staff, Mr Marsh did not explain the reasons for his earlier than planned departure.

He said: 'I was brought in for up to a two year period to turnaround the organisation. I would like to reassure you that this doesn't mean I will be leaving in the next few months - I will remain until a new chief executive is recruited.

'Indeed the process to recruit a new chief executive can take many months, so it is right that the Board kick this off in the new year.

'I remain absolutely focussed on supporting you and getting EEAST into a position of stability and high performance, and you can be assured this will be the case over the coming months.'

The service's response times have improved under Mr Marsh's stewardship.

For the last two weeks it was the best performing ambulance service in the country for the most urgent calls - known as Red 1.

But in Norfolk, Suffolk and Cambridgeshire, they have remained off target.

UNISON branch secretary Fraer Stevenson questioned the timing of the announcement, with staff facing their busiest time of the year.

'It's very disappointing that this decision has been made while we are in such a fragile state,' she said. 'To say we're in recovery is a small part of a very big picture, and while we've made good progress over recruitment, we are very far from out of the woods.'

Do you have a health story? Email tom.bristow@archant.co.uk