Hospital trusts have been left counting the cost after health tourists refused to pay medical bills worth up to £20,000 each.

Now officials have had to call in debt collectors to hunt down the foreign patients around the world and try to get the cash back.

Surrey and Sussex Healthcare NHS Trust, which is responsible for Crawley and Horsham hospitals, is owed £117,000 from 38 foreign national patients for medical treatment in the last 12 months.

Amongst the unpaid debts are a £19,500 bill for a Ukrainian patient to receive treatment for a peripheral nerve disorder and £11,000 for a patient from Sri Lanka to have a limb amputated.

More than a third of all foreign national patients treated have not paid their bills in the last three years leaving the trust out of pocket to the tune of £220,000.

East Sussex Hospitals NHS Trust, which runs the Conquest Hospital in St Leonards and Eastbourne District General Hospital, is also still chasing payments from foreign patients.

An Argentinian patient had £3,000 of treatment without paying a penny in 2009/10 and a South African patient has still to pay a bill worth £6,640 from 2007/8.

Over the last three years the trust has been left £20,000 out of pocket after treating ten patients who then wouldn't pay their bills.

NHS rules mean that people who do not normally live in the UK are not automatically entitled to use of the health service free of charge.

Visitors may be exempt from payment for treatment received in Accident and Emergency wards, certain diseases where treatment is necessary to protect the wider public health and in some cases of sexually related diseases or mental health problems.