The Medical Defence Union (MDU) says it has come across a number of cases in which patients have 'attempted to proposition doctors' via the internet.

Doctors may be tempted to respond to patients who make unsolicited messages on social networking websites, if only to politely reject their advances, the MDU says.

But Dr Emma Cuzner, MDU medico-legal adviser, warned: 'The pitfalls posed to doctors using soical networking sites by inadvertently breaching confidentiality or posting unprofessional content, such as photos, have been well documented. But doctors may be less prepared for patients using sites like Facebook to ask them out on a date.

'Some doctors have told the MDU they feel it would be rude not to reply, if only to politely refuse, but given this is not a professional route of communication, any correspondence of this sort would clearly stray outside the doctor/patient relationship.'