Changes to the working conditions of ambulance crews could lead to fewer emergency vehicles on the road and put staff under intolerable pressure, says an experienced former 999 man.

An email sent to all East of England Ambulance Service staff proposes that the length of meal breaks is reduced and existing measures to reduce late finishes scrapped.

Gary Sanderson, who lives in Stevenage and was an ambulance officer for more than 30 years, said: “It’s a tough and very demanding job, both physically and mentally. Crews normally work 12 hour shifts and need to have regular breaks to perform at their best. They need to make split second decisions to save lives.

“If they don’t get regular breaks they will become ill and go off duty sick, leaving an ambulance or response car not staffed. “The problem is late finishes. Crews receive a late call approaching their finish time, which sees them finishing up to three hours after their shift should have finished.

“A crew recently finished four hours after a 12-hour night shift – a 16-hour shift is clearly unacceptable.

“The call demand is increasing each year for all ambulance trusts in the country, and the rise in inappropriate calls needs to be addressed urgently.”

Fraer Stevenson from union Unison said: “We have crews regularly working 14 or 15 hour shifts and recently one crew was forced to work a 20.5 hour shift. This is a huge risk for patient safety and staff welfare.

“The chief executive and ambulance trust chairman have both acknowledged staff are exhausted and working under enormous pressure.

“Committed, experienced staff are voting with their feet and walking away.”

A spokesman for the ambulance trust said: “We tabled a proposal with Unison to help reduce late finishes for staff and reduce ambulance waits for patients. We are pleased Unison has agreed to re-enter negotiations on these proposals – proposals that will benefit both staff and patients.”