''After landing, our Dutch exchange officer, on my squadron, called Dutch Military to discuss the event.

''The controller insisted that no other radar contact was made at the time in the vicinity.''

The spooked pilot said the UFO looked nothing like any plane he knew was in any service.

Though he described the plane as being as big as a Hercules it had a smaller wingspan and the engine exhaust had ''a light blue afterburner-type flame which was steady but changing in intensity''.

Two other RAF fighter jets flying out from Laarbruch nearly collided head-on with the UFO and saw it at the same time, the pilot said.

''These aircraft would have been close to being head-on to the UFO, while from our Tornado, the UFO came down our right-hand side at a great speed (ie, coming from the direction of the UK).

''We were doing 0.8 Mach and it readily overtook us.''

He went on: ''This was definitely not a Russian satellite - I am 100% certain of that.

''This was a large 'aircraft' and I could see the detail of the lights and the engine area.

''I have never seen anything like it.''