NEARLY 500 ambulances were forced to queue outside Worcestershire's hospitals for more than half an hour, according to shock new data.
Figures for just one month reveal how massive pressure on hospital staff is stopping patients being transferred into the care of in-house staff straightaway.
The tactic, known as 'stacking', has been criticised as "extremely concerning" by critics, who say NHS chiefs need more help.
The Government has produced a raft of data on how acute trusts are performing for queuing ambulances.
The latest figures reveal that between Friday, February 28 and Sunday, March 30, considered to be the final 'winter' period for the NHS, 488 ambulances were stacked up for more than 30 minutes.
In the worst performing weekend, from March 21-23, 61 ambulances were affected.
Worcestershire Acute Hospitals NHS Trust says it was a "challenging month" and that the average offload time was 17 minutes.
But a spokesman for West Midlands Ambulance Service said: "Any delay means that ambulance is unable to respond to the next patient, it puts additional pressure on the ambulance service."
The findings have been criticised by Councillor Joy Squires, Worcester's Labour parliamentary candidate, who is campaigning against proposals to shut the city's Farrier Street walk-in clinic.
She said: "Just over 12 months ago I spent 12 hours with an elderly neighbour in A&E at Worcestershire Royal Hospital who had a fall and needed help.
"It was at that point, after waiting in that cubicle with her for those 12 hours that I realised there was a problem.
"The staff were fantastic but what became clear to me was the appalling strain they were under.
"I saw people lined up on trolleys in the corridor, and as that day went on I saw very much the problems we have. It's a real concern."
The data does not differentiate between the hospitals in Worcestershire, although the royal is the busiest.
The figure includes all ambulances attending a site, including those transferring patients to and from appointments, acute medical units and mental health facilities, which the trust says often take longer.
But around 80 per cent of them do attend A&E.
The trust says the patients do go inside and are often treated inside the corridors, meaning they are not forced to wait in the actual ambulances.
Stewart Messer, chief operating officer at the trust, says it is still meeting national targets for patients being seen and treated after arrival.
"Worcestershire Acute Hospitals Trust prides itself on its strong working relationship with West Midlands Ambulance Service," he said. "On a daily basis our staff and ambulance crews work together to ensure patient safety and quality of services.
"March has been a challenging month as 12,861 patients attended the accident and emergency departments compared to 11,560 in March last year.
"The average time to offload at A&E was 17 minutes.
"However, the important and most critical target is the average time for patients to been seen and treated after arrival.
"In March Worcestershire patients waited, on average, 48 minutes from arrival to being treated - the national target is to be treated in less than 60 minutes."