“The shocking truth is that 450 to 600 lives are being unnecessarily lost each year because of poor care. Your chances of avoiding death or disability can turn on when your accident happens and to which hospital the ambulance takes you.”

Mr Leigh added the true situation “could be worse than we think”, because 40% of A&E departments did not provide survival statistics.

Experts say major trauma centres need 16-18 consultants for round-the-clock cover – yet the average hospital currently had just four.

The Department of Health (DoH) said it was introducing regional trauma networks, to take patients by ambulance to a specialised centre.

The NAO report assessed progress in setting up the networks in each region.

For the North West, it concluded simply: “Trauma care is being reviewed.”

Last night, a spokeswoman from the Royal said the TARN figures were “an incomplete picture” of standards in trauma care.

She said: “Only around 60% of hospital trusts, who deal with major trauma, have submitted data.

“This data is collected in different ways by different hospitals.

“Some hospitals have better resources than others for collecting data and this may affect the quality and completeness of the data. The data published on TARN about this Trust is incomplete.

“Our patients should not be concerned by these statistics, because they do not give an accurate picture of the care we provide.

“We review all deaths and constantly strive to improve care for our patients. We are confident that we provide high-quality care.”