LONDON - SECRET files containing personal details about British Royal Air Force (RAF) staff including their extra-marital affairs and use of prostitutes has been stolen, the Guardian newspaper said on Monday.

The information was on three unencrypted computer hard drives which disappeared from RAF Innsworth in Gloucestershire, southwest England, in September last year, the paper said.

It quoted an internal Ministry of Defence memo, obtained under freedom of information laws, saying if it fell into the wrong hands, the data could 'grab front page status' and 'the reputation of the service will be tarnished'.

'This information included details of criminal convictions, investigations, precise details of debt, medical conditions, drug abuse, use of prostitutes, extra-marital affairs,' the memo said.

'This data provides an excellent target list for foreign intelligence services, investigative journalists and blackmailers.' Details of the memo, which referred to information gathered during vetting procedures, will be broadcast on a BBC programme on Monday.

A Ministry of Defence spokesman could not confirm the nature of the information which was stolen.

But he added: 'There is no evidence to suggest that the information held on the hard drive... has been targeted by criminal or hostile elements.' -- AFP