The interim chairman of the East Anglian Ambulance Trust has resigned early.
Dr Geoffrey Harris was brought in to turn round the leadership of the trust after it failed to meet targets for getting to emergencies on time.
In a statement, he said much work remained to be done but that the trust now had the right chief executive and was making improvements.
Work will now begin to recruit a new chairman.
A Government minister has called for a shake-up in ambulance response targets in rural areas following the death of a young chef in Norfolk.
It took two hours for an ambulance to get to 26-year-old Peter Nelson who had suffered a brain haemorrhage.
His local MP has described it as completely unacceptable and wants an urgent review of the time it takes paramedics to reach urgent cases.
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A health minister and Norfolk MP has called for a major shake-up of response times after yet another story emerged of alleged delays by the East of England Ambulance Service.
26-year-old chef Peter Nelson died after collapsing at his home in Blakeney, in North Norfolk, after waiting nearly two hours for an ambulance.
Norman Lamb, who's the minister in charge of care and support, said rural areas were being neglected as trusts focused on meeting easier urban response-time targets.
"We need to re-think these targets because they distort behaviour," he said.
"I don't have a complete blueprint for the answer but I'm clear there is a massive risk that the current system is distorting clinical priorities and rural patients are suffering as a result."
The East of England ambulance service is asking people to think twice before dialling 999 on New Year's Eve.
It is expecting New Year's Eve and New Year's Day to be its busiest time and is asking people to make sure it really is an emergency before calling the service.
Although the Christmas period was quieter than last year, the service took 40 more calls on Christmas day than in 2012.
For winter health advice visit the East of England Ambulance service website.
The region's ambulance service had a busy Christmas day, taking more than 2,700 emergency calls.
That's a hike of around 300 calls compared to an average day, and 40 more than last Christmas.
The East of England Ambulance Service said calls ranged from chest pains and choking, to assaults and births.
Just over 1,200 patients were taken to hospital. They're expecting New Year's Eve and New Year's Day to even busier.
However, there was a decrease of about 360 calls over the three days of the Christmas period compared to 2012.
Whilst it’s encouraging we’ve seen a slight decrease in the number of calls compared to the same period last year, we’re still seeing an increase each Christmas Day.
Our staff are working as hard as ever over the period and I’m proud of all those who have been carrying out lifesaving work for the Trust over the past few days.
From our call handlers, to the crews out on the roads, and everyone else - I’d like to say a huge thank you to them all.
- Total 999 calls on Christmas Day - 2,717
- People taken to hospital by EEAST on Christmas Day - 1,241
- Total calls from Christmas Eve to Boxing Day - 7,813
The troubled East of England Ambulance service has decided to withdraw its current foundation trust application while it works to make major improvements.
The announcement was made at today's board meeting.
The trust said it would not attempt to re-apply until "sustainable improvements have been made to the service patients receive".
Chairman Geoffrey Harris added: "I am focused on patients and improving our service to them.
"Transforming our services and becoming a high-performing organisation will take time, but it is the most important challenge to address."
In December 2012, health watchdog Monitor deferred an application by the service to become a foundation trust for 12 months over concerns about its failure to meet response-time targets.
Foundation trust status means decision-making powers are passed from central government to a trust's governors and members.
A sixth director has quit the beleaguered East of England Ambulance Service.
The Director of Emergency Operations Neil Storey has left after 14 years with the ambulance trust.
Mr Storey is the latest director to resign after sustained criticism of the East of England Ambulance Trust by regulators and politicians over slow response times in rural areas and poor leadership.
Five non-executive directors resigned from the Trust in June.
The Trust said he was "taking the opportunity to move onto pastures new whilst a directorate restructure takes place internally."
Chief Executive Andrew Morgan said: “I would like to personally thank Neil for his absolute commitment and dedication to the ambulance service over the last 14 years.”
Essex MP Priti Patel has welcomed the resignation of five non-executive directors of the East of England Ambulance Service NHS Trust.
The Conservative MP for Witham led a parliamentary debate on the short-comings of the Ambulance service on Tuesday.
Ms Patel said: “The priority now for the Trust is to continue to improve services to patients, get their finances in order and appoint new non-executive directors who have the skills and expertise to achieve this.
"A new leadership team at the Trust will help restore public confidence and support the work being undertaken by paramedics and other staff on the frontline.”
The remaining non-executive directors of the East of England Ambulance Service have resigned. Margaret Stockham, Paul Remington, Anne Osborn, and Phil Barlow are all leaving with immediate effect.
The Service has been the subject of recent criticism over response times.
Dr Geoff Harris, new Chair of the Trust, said: “This is a line in the sand for the Trust and I thank the Non-Executive Directors for their collective action. "
"We must maintain our focus on continuing to drive up the service to patients whilst I focus on putting a new Board in place.”
The Ambulance Trust says the recruitment process for new Board members has started and two of the posts are already being advertised.
One of five Non-Executive Directors at the East of England Ambulance Service has resigned. Caroline Bailes announced her decision to step down earlier today.
Yesterday MP's debated the state of the service in parliament, following criticism about their poor response times. MP for Witham, Priti Patel, has welcomed the news but said there are still four more board members "who should quit too".