An RAF fighter jet and a light aircraft almost collided over the Norfolk countryside, it emerged today.

A Typhoon warplane, which had been diverted to land at RAF Marham as a training exercise, took evasive action to avoid a single-engined Cessna 10 miles north-east of the base near Great Ryburgh.

The Typhoon pilot, who dived beneath the civilian aircraft, estimated he passed within 300ft of it. He rated the chances of collision during the incident, which happened on July 31, as 'high', according to a report released by the UK Airprox Board, which examines near misses.

The Cessna pilot, who did not see the Typhoon before it passed beneath him, as he flew at 2,600ft, rated the chance of a collision as 'medium'.

He said he telephoned the control tower at Marham before taking off from a nearby airstrip and had been told there would be Tornado aircraft operating from the base but was not given any specifics.

The Marham air traffic controller said he was controlling three different types of aircraft at the time the near-miss occurred, just after 11am. He did not see the Cessna on his radar until he received a warning that another plane was in front of the Typhoon.

He said when he radioed to warn its pilot, he was told the jet had just passed beneath the Cessna.

HQ Air Command stated: 'The Typhoon pilot was in a reasonably busy phase of flight, descending and configuring his aircraft for an approach, so his lookout would have been compromised.'

In its summary, the report says: 'The Board felt that the C172 pilot had done his best to inform Marham of his intentions to fly close to their radar pattern, had called them on the radio, and had attempted to route away from their normal radar pattern.

'The Board discussed at length the cause of the Airprox and eventually agreed that Marham ATC had allowed the Typhoon pilot to fly into conflict with the C172 [Cessna].'

It added: 'The incident had just stopped short of an actual collision where safety margins had been reduced to the minimum.'