Delays to ambulances attending the most severe 999 callouts are putting lives at risk in the East of England, figures have revealed.

Unison said that a combination of staff shortages and increased demand means ambulance crews can struggle to respond to emergency calls on time.

Freedom of Information data obtained by Newsquest from the East of England Ambulance Service show ambulance crews were unable to respond to more than 43,000 of the most life-threatening 999 calls within national targets.

It’s a figure that has risen year-on-year from 7,846 in 2018 to 12,331 in 2021, an increase of more than half.

Requiring an immediate response to life-threatening conditions, calls graded as Category 1 relate to incidents such as an individual suffering a cardiac or respiratory arrest and require intervention in under seven minutes.

It comes as figures published by the NHS revealed ambulance crews in England could not respond to almost one in four 999 calls in October last year.

Glenn Carrington, a senior paramedic, and Unison’s East of England Ambulance Service branch chair said: “Ambulance staff, from paramedics and EMTs on the road, to our call handlers and dispatchers in control rooms, to our make ready operatives and mechanics in the workshops, all work as hard as they can to make sure people get the help they need when they dial 999. It is heartbreaking that this isn’t happening in all cases.

“We all joined the service because we want to be helping patients, not waiting in a hospital car park, or bearing the brunt of rightfully frustrated people who have had to wait long periods for an ambulance to arrive. Staff are leaving the profession because they aren’t getting to do the job that they love.

The figures also show that of the 5.1 million emergency calls received between 2018-22, more than two million received a response exceeding 15 minutes.

Laying bare the extent of the delays, the data reveals that one patient classified with a life-threatening condition was forced to wait more than 90 minutes for an ambulance to arrive.

Ambulance services in England have experienced a mass exodus in staff in the past year with nearly 7,000 leaving their jobs.

A survey conducted by the charity Mind in 2021 revealed mental health had worsened across emergency services, but that ambulance staff were worst impacted.

Of the 4,000 staff and volunteers surveyed, only 26 per cent reported their current mental health as ‘very good or ‘good’.

Carrington added: “With these figures we are seeing the results of over a decade of neglecting the NHS by the government. When you spend 14 years failing to invest adequately in health services and the staff that deliver them, those services will suffer, especially when facing an increase in demand.

“Delays with ambulance responses, and issues within the NHS, seem to have been accepted as the norm the last few years, but staff and patients deserve better from the government. To turn this around the NHS, and the staff that deliver it including hard working ambulance staff, need proper long-term recognition and investment.”

A spokesperson for the East of England Ambulance Service said: “We have significantly improved our response times over the past year but there is more work to be done.

“We are working across the NHS to address delays for our crews handing over patients to hospitals, which are main barrier to meeting response times.

They added: “We are also working with partners to reduce demand on our services and emergency departments, while recruiting more staff on the frontline and in support roles, so we can respond more quickly to those in need.”