Image caption The Tornado sign was captured during a flight

A prank by an RAF Tornado crew spotted flying with a sign saying "I'm with stupid" has been laughed off by the Ministry of Defence.

The crew, from RAF Lossiemouth, was photographed during a high-speed exercise through hills in Snowdonia.

Plane-spotters captured the navigator holding up a piece of paper with the joke pointing to the pilot.

An RAF spokesman said it was a "light-hearted moment" and insisted the crew had not endangered the aircraft.