Growing numbers of staff leaving ambulance trusts could lead to a repeat of patients waiting in pain as pressure hits a “broken” health system this winter, the Liberal Democrats have warned.

Figures obtained by the party through freedom of information requests show a 51% increase in the annual level of staff departures across all 10 ambulance trusts in England since 2019-20.

The vacated roles, which include jobs such as paramedics, control room staff, mechanics and managers, increased to 6,968 in 2022-23 from 4,609 three years earlier.

West Midlands Ambulance Service had the most departures last year at 1,046, which is a turnover rate of 14%.

South Central Ambulance Service had 927 departures and South East Coast Ambulance Service had 802 – turnover rates of 21% and 18% respectively.

There are currently 2,954 vacancies across all ambulance trusts in England, the Lib Dems said.

Yorkshire Ambulance Service was found to have the highest vacancy rate in 2022-23 with 17% of posts not permanently filled – a shortfall of 1,157 staff.

The trust said it covers the vacancies with a combination of overtime and the use of agency and back-up staff.

South Central had a staff shortage of 869 posts – a vacancy rate of 16%.

Demand pressures across the NHS last winter led to lengthy treatment delays as ambulances were stuck outside hospitals with patients who could not be admitted to overwhelmed accident and emergency departments.

In December, the average ambulance response time for a category two call, which includes suspected heart attacks or strokes, was over one hour and 30 minutes. The target response time is 18 minutes.

Performance has since improved, but there are concerns that a spike in demand this winter may lead to more delays.

Daisy Cooper, Lib Dem spokeswoman for health and social care, called on the Government to launch a recruitment drive to boost staffing levels.

She said: “This Conservative Government has run our health services into the ground and these figures show that paramedics are voting with their feet.

“With patients struggling to see a GP at the front door of the NHS and unable to access social care at the back door of the NHS, ambulance crews are unfairly caught between a rock and a hard place, picking up the slack from a health and care system that is broken at both ends.

“The shortage of NHS staff has caused untold pain for millions of people across the country, especially those left to wait for hours in pain for an ambulance to arrive.”

She added there is “no time to waste” and called on the Government to introduce measures to prevent ambulance services being “again put under unsustainable strain”.

Unison, which represents ambulance staff, said pressures on workers had been created by a lack of Government investment.

Sara Gorton, the union’s head of health, said: “Ambulance staff are under intolerable pressure because services are over-stretched.

“Spiralling 999 calls and endless queues outside A&E departments have left them burnt out. It’s no wonder so many decide they’ve had enough.

“Ministers must reverse years of neglect and invest in ambulance services. This might persuade staff to stay and ensure patients get the care they need.”

A spokesperson for South East Coast Ambulance Service said: “We have recruited 476 frontline road staff as well as 540 staff to work in our 999 and 111 operations centres in the last 12 months.

“We are committed to providing high-quality care to our patients and part of that includes continuing to improve recruitment and retention levels to ensure we have the required staff to respond to those who need us, while providing colleagues with the support they need to carry out their challenging roles.”

A Department of Health and Social Care spokesperson said: “We are boosting the number of paramedics by up to 15,600 by 2031-2032 as part of the first ever NHS Long Term Workforce Plan, backed by over £2.4 billion over the next five years and there are around 700 more paramedics in the NHS than last year.

“As part of this Urgent and Emergency Care Recovery Plan ambulance services are receiving £200 million of additional funding this year, alongside over 800 new ambulances.”