'Health service tourists' fly in to the UK and make their way straight to the accident and emergency department at St Thomas' Hospital, Labour MP Kate Hoey has claimed.
The Vauxhall Labour MP intervened during a speech by Tory David Davis in the House of Commons on Wednesday to claim that "...people come from Heathrow Airport to the A&E department at my local hospital, St Thomas', with something that they knew perfectly well they had before they came.
"It is not as simple as saying, 'We must look after the sick'; clearly there are limits. This is a form of health service tourism."
A spokeswoman for Guy's and St Thomas' NHS Foundation Trust told the London SE1 website: "Department of Health rules and medical ethics mean we must treat overseas visitors when emergency or urgent care is required at our hospitals.
"Similarly, we are required to identify and charge those patients who are not entitled to NHS treatment.
"We have a dedicated overseas visitors' team which supports frontline staff across the hospital and follows up patients, where staff have identified that they may not be entitled to NHS treatment.
"We have also implemented more rigorous checks on patients attending our A&E at St Thomas' if they go on to receive subsequent treatment in the trust."
Mr Davis, a former Tory frontbencher, had cautioned against plans announced in the Queen's Speech to limit access to NHS services by non-UK citizens.
"I am not at all sure, however, that I agree with the Government's idea of withholding health care from people coming to this country, and I return to my point about acting firmly without being uncivilised – without being barbarous," he said.
"I find it difficult to imagine doctors in an accident and emergency department in a London hospital finding someone with a foreign accent on a trolley in front of them and asking, 'Where are you from? If you are Hungarian, you can be treated; if you are Bulgarian, you can't.'
"I do not see how that is going to work. Most of us get reciprocal health care if we go to European countries on holiday, to retire or to live, so I do not see how we are going to amend our provision.
"I am not sure, in my heart of hearts, that I want to say to someone who has been run over in the street, 'You can't have health care, because you're a foreigner.'"