Paramedics in the east of England are taking nearly three minutes longer to reach the most seriously ill patients compared to three years ago, according to figures.

Data from the Health and Social Care Information Centre shows category A ambulance call-outs, which relate to life-threatening conditions such as heart attacks and strokes, are taking an average of 67 seconds longer than in 2011.

At the East of England Ambulance Service NHS Trust (EEAST), the rise is two minutes 48 seconds – though it still meets the response requirement.

EEAST chief executive Dr Anthony Marsh said the trust was recruiting extra paramedics and putting additional ambulances on the roads to help.

Shadow health secretary Andy Burnham said the figures raised concerns that lives were at risk. He added: “For people who’ve suffered cardiac arrest or a stroke, every second counts and that is why this slump in standards cannot continue.”

A Department of Health spokesman said: “We know some ambulance trusts are under pressure, carrying out over 850 more journeys every day since 2010, but the NHS continues to respond to the majority of the most life-threatening cases in less than eight minutes.

“We’re giving the NHS extra support to keep services sustainable year-round, and where performance has been poor, action has been taken to address long-standing problems with new chief executives brought in at East Midlands and East of England ambulance services with clear recovery plans in place.”

Dr Marsh, who joined EEAST in January, said the trust was recruiting 400 student paramedics by next April, up-skilling emergency medical technicians and emergency care assistants and upgrading its ambulance fleet.

He added: “These actions are starting to make a difference and, as more staff are recruited and trained, delays will reduce further and performance will improve. In particular, we’re making progress in areas that have for some years seen poor performance and we’re working hard to ensure the rest of 2014 sees more progress and improvement across the board.”