About a third of hospitals in England and Wales are ignoring government advice to charge foreign visitors for NHS treatment.
Guidance published in 2004 stipulates hospitals should check whether foreign nationals are entitled to free care. But a third of overseas visitor managers polled by their association admitted patients were not routinely asked about their entitlement.
The Department of Health said those not entitled to free care should pay.
Tunde, not his real name, lives in Lagos in Nigeria and has been suffering with heart trouble for the past three years. But, instead of paying for treatment at home, he travels to the UK for free care on the NHS. "I have an NHS card. I registered it through the GP. I book an appointment with a GP and I am referred to the hospital," he said.