A foreigner who broke her leg on a visit to Britain while trying to walk in a pair of Vivienne Westwood high heels has won her battle with the NHS over a £2,500 bill for surgery.

Last month ministers announced a crackdown on "health tourists" who came to this country to benefit from the free NHS but stressed that emergency treatment would remain free.

The case of Elizabeth Ross, an artist from Mexico who spent 10 days in St Thomas' hospital, London, highlights the difficulties NHS trusts face in deciding who to charge for treatment.

Ms Ross arrived in London in October 2002 for a lecture tour. She stayed in the flat of a friend where she tried on a pair of high-heel shoes made by the designer Vivienne Westwood. Tottering around the flat in the shoes she lost her balance, fell awkwardly, and broke her leg.

An ambulance took her to St Thomas' where she was treated in the accident and emergency department before being admitted to the ward. Surgeons said they would have to operate but Ms Ross explained she did not have insurance and could not afford to pay.

The operation went ahead and the break was so severe that she needed a titanium plate secured with four screws inserted in her leg. She remained in hospital for more than a week and spent months recuperating after returning home to Mexico.

She was contacted in autumn last year by CCI Legal Services, a debt-collection agency in Wales, demanding payment. She wrote to Guy's and St Thomas' NHS Trust on 6 November 2003 protesting that the hospital had known she was unable to pay before proceeding with the operation.

"I didn't break my leg for the pleasure of being treated by the NHS," she said.

Six weeks after receiving the letter, on 24 December, St Thomas' wrote off the debt. A spokeswoman said that as the surgeons had decided to operate in the knowledge that she could not pay, it had been wrong to pursue Ms Ross for payment.

Jim Johnson, chairman of the British Medical Association, said: "I would expect any doctor faced with an emergency to treat the patient and ask questions later. We are not going to be tax collectors for the Government."