Chris Thompson, a specialist nurse in accident and emergency, is offered staff jobs wherever he goes in the NHS but he prefers to remain freelance, working for a commercial agency.

His hourly rate ranges from £19 to £26.50 and on bank holidays it can go as high as £48. He can earn twice an NHS salary and take days off with his wife, Maria, also a nurse, when he wishes. "I earn what we would both earn if we had staff jobs in the NHS ­ about £35,000 a year. It would be quite feasible to earn more ­ I don't work particularly hard," he said.

Mr Thompson, 31, has worked with his agency for six years, commuting from his home near Evesham in Worcester to work in hospitals in Bristol and Gloucester. Mr Thompson said: "People stay with agencies for the convenience. When there is money in the bank I take time off if I want to. When I started, there were three agencies in Bristol and I know of seven now.

"There were half a dozen A&E specialist nurses like me but there are probably 500 on my agency's books now. But if the worst comes to the worst I can always get an NHS job."

Joanna Doyle, an intensive care nurse, left the NHS in January and has worked for an agency in Birmingham since then. She earns more as a temporary nurse than she did in charge of the intensive care unit and now has time to study for her MA in medical law.

"I like to work long days from 7.30am to 9.30pm. Last weekend I worked Friday to Sunday and came out with £523 in my hand after tax. I could never hope to achieve that in the NHS," she said. "I don't think we are valued as a profession. I have no desire to go back to an NHS job."