A strain of bird flu has been found in a dead swan in Scotland, health officials said last night.

The Scottish Executive said preliminary tests had found "highly pathogenic H5 avian flu" in a sample from the bird.

The H5 strain is a contagious strain and can fatal to birds.

Further tests are being carried out to see if the strain is the deadly H5N1, which can be fatal to humans if they come into close contact with birds.

The European Commission said the dead swan was found in Cellardyke, a small coastal town in Fife, nine miles from St Andrews.

A 3km "Protection Zone" has been thrown up round the area where the swan was found, along with a "Surveillance Zone" of 10km, said a statement from the Scottish Executive.

Chief veterinary officer for Scotland Charles Milne said: "Whilst disease has yet to be confirmed, this is an important development.

"Bird keepers outside the protection zone should redouble their efforts to prepare for bringing their birds indoors if that becomes necessary."

The statement from the Scottish Executive said: "The exact strain of the virus is not yet known, tests are continuing and a further result is expected tomorrow.

"Whilst highly pathogenic avian influenza has been found, the full type is not yet known at this stage.

"Avian influenza is a dis-ease of birds and whilst it can pass very rarely and with difficulty to humans this requires extremely close contact with infected birds, particularly faeces."

Samples from the dead swan were being sent for analysis at the EU's bird flu laboratory in Weybridge.