London has warned airlines around the world not to allow Edward Snowden, who leaked information on US government surveillance programs, to fly to the United Kingdom.

A travel alert, dated on Monday on a Home Office letterhead, said carriers should deny Snowden boarding because "the individual is highly likely to be refused entry to the UK".

The Associated Press saw a photograph of the document taken on Friday at a Thai airport. A British diplomat confirmed that the document was genuine and was sent out to airlines around the world. Airlines in Thailand, Malaysia and Singapore also confirmed the alert had been issued.

The diplomat said such alerts are issued to carriers that fly into the UK and any carrier that brings Snowden will be liable to be fined $3,130.

Snowden would likely have been deemed by the Home Office to be detrimental to the "public good", said the diplomat, who was not authorized to discuss the matter publicly.

AP