The Jaguar was on an exercise with two other Jaguars

The high-speed Jaguar fighter, from RAF Coltishall, in Norfolk, was on a low-level training exercise over the north-east of England in July 2002, when the incident happened.

A report from the Civil Aviation Authority (CAA) said an inbound passenger plane, with up to 50 people on board and the RAF jet came within 100ft of collision.

The CAA described the incident, shortly after 1400 BST on 2 July 2002, as one of the most serious ever.

The incident involved a RJ85 passenger plane flying from Brussels to Newcastle and happened about 22 miles south east of Newcastle Airport.

Wrong assumption

The Jaguar pilot was involved in a low-level training exercise with two other aircraft over the north-east of England.

The report says the fighter pilot began a steep climb after the exercise - directly into the path of the inbound passenger plane.

It says that instead of informing air traffic controllers at Newcastle Airport of his intention to climb, he spoke only to RAF personnel in London.

The RJ85 passenger plane was flying to Newcastle Airport

Staff in London told him another aircraft was just one mile away. But the Jaguar pilot wrongly assumed this was another military jet flying at low-level.

The report said cloudy conditions on the day added to an already dangerous situation and that the Jaguar pilot took an "unnecessary risk".

The report says when the passenger plane pilot was asked 17 seconds after the near miss by a Newcastle Airport controller if he had received a message to take avoiding action, the pilot replied "it's a little bit late".

'Very serious'

After the incident the RAF changed its procedures involving crews training close to civilian air space.

A Ministry of Defence spokeswoman said an area of controlled airspace had been set up at Newcastle Airport which aircraft could only enter after contacting a controller.

The report said: "As it was, the subsequent encounter with the RJ85 was so close that only chance had prevented a collision."

The RAF said it regarded the near miss as "very serious" and that a "strong directive" had been issued to all jet pilots to ensure such a similar incident could not happen again.

The pilot was not disciplined over the incident and the RAF said no actual rules had been broken.