London, June 20 : A British police helicopter crew gave chase to a UFO after it attacked their aircraft near a military base.
The mystery aircraft zoomed straight at the chopper as the three-man cop crew prepared to land.
The pilot was forced to bank sharply to avoid being hit by the mystery aircraft as the helicopter was returning to the Ministry of Defence base of St Athan, near Cardiff.
The crew, who described the UFO as 'flying saucer-shaped', then gave chase, getting as far as the North Devon coast before they ran low on fuel - - and the UFO escaped, it was reported.
The police aircraft was hovering at 500ft and waiting clearance to land on the night of June 7, when those onboard spotted the other craft hurtling towards them from below.
"It closed in at great speed, aiming straight at the helicopter," The Sun quoted a source, as saying.
"The chopper had to swerve sharply to avoid being hit. The guys said if they'd stayed where they were, they'd be dead - it would've been a direct hit.
"They are convinced it was a UFO. It sounds far-fetched, but they know what they saw.
"These guys are hardened professionals and know people will take the mickey, but they are certain they saw a UFO.
"After the near-collision they decided to follow it to find out what the hell it was. They belted across the Bristol Channel in pursuit, but it was too quick. They got to the North Devon coast and had to turn back because they were running low on fuel," the source added.
The chopper is packed with hi-tech cameras and surveillance gear, but the UFO somehow avoided being caught on film.
Strangely, the crew could not see the craft with night-vision goggles - but all said it was 'clearly visible' to the naked eye.
South Wales Police said: "We can confirm the Air Support Unit sighted an unusual aircraft. This was reported to the relevant authorities for their investigation."
The MoD, which usually investigates UFO sightings, said: "We've heard nothing about this. But it is certainly not advisable for police helicopters to go chasing what they think are UFOs."