The Medicines and Healthcare products Regulatory Agency (MHRA) has linked up with Interpol to combat the illegal sale of medicines over the internet.

A number of co-ordinated visits to UK addresses believed to be linked to such practices were carried out by MHRA investigators last week.

Unlicensed and often fake medicines claiming to treat conditions such as impotency, diabetes, obesity and hair loss are among those believed to be sold from the UK.

MHRA head of operations Danny Lee-Frost commented that people can be at "considerable risk" if they buy medicines from illegal websites.

He added: "A medicine bought in this way has no guarantee that it is safe or that it is effective and can in fact be harmful."

Mr Lee-Frost said the MHRA operation demonstrated the agency's commitment to safeguarding public health, while it should also have issued a "stark warning" top unscrupulous individuals involved in the supply of fake medicines.

Earlier this week, pharmaceutical firm Pfizer reported that up to 90 per cent of drugs advertised on the internet are fake.