A hospital in England is chasing a £350,000 bill racked up by a Nigerian mother who flew to the country to give birth to twins in 2015.
It comes as Britain is faced with a large scale of abuse of its crumbling NHS by health tourists.
The woman, who has not been identified, had a caesarean section at Luton and Dunstable University Hospital.
She was transferred there from another hospital because of pregnancy complications and her twins then spent two months in intensive care.
The British Government has been accused repeatedly of failing to clamp down on health tourism, which is thought to cost up to £280million a year.
Patients face fewer checks on eligibility for free treatment than in other countries.
The bill comes to light at a time when the NHS is in the grip of an unprecedented winter crisis, itself blamed on lack of funds.
Imperial College Hospitals in West London also said it was chasing a £319,895 bill for a woman who gave birth to triplets.
Staff at the trust have since disclosed that this autumn they looked after a 43-year-old Nigerian woman who gave birth to quads.
She went into premature labour on the flight to London and one of the babies died.
The costs of caring for the surviving three infants have passed £100,000 and staff predict a final bill of half a million pounds.
Doctors are faced with a dilemma over eligibility because they are obliged to provide immediate medical care regardless of a patient’s nationality or whether they can pay.
Authorities believe UK hospitals are being targeted, in particular by wealthy Nigerian mothers-to-be.
One of the most celebrated cases is that of Bimbo Ayelabola who racked up a bill of £145,000 in giving birth to quintuplets in Homerton Hospital, East London, in 2011, and has not paid the money back.
