London - The British government tried to cover up one of the country's most famous sightings of an Unidentified Flying Object (UFO), a parliamentary watchdog ruled on Tuesday.

The Rendlesham Files, which were finally released last Thursday, contain eye witness accounts by United States Air Force officers at a military base close to Rendlesham Forest, eastern England, who saw a brilliantly lit object land in the forest in December 1980.

Several people had complained to the parliamentary ombudsman, Ann Abraham, that the Ministry of Defence had refused to divulge full details of the witness accounts.

Abraham ruled the ministry had "withheld three documents relating to reported sightings of unexplained aerial phenomena in 1980, the Rendlesham Forest UFO incident".

A ministry spokesperson said the files had not been deliberately withheld and had always been available to anyone who asked.

In late in December 1980, officers investigating what they thought must be a crashed plane saw a triangular "strange glowing object" that sent nearby farm animals into a frenzy.

"The object was described as being metallic in appearance and triangular in shape, approximately two to three metres across the base and approximately two metres high," reads the file.

"It illuminated the entire forest with a white light," it added.

"The object itself had a pulsing red light on top and a bank of blue lights underneath. The object was hovering, or on legs."

Sceptics say the witnesses were merely seeing the beam from a lighthouse on the nearby coast.

But the report adds that the next day three depressions two metres in diameter were found in the forest and readings of beta and gamma radiation were recorded.

Until last week, only around 20 members of the public had seen the file. The government said it would also be publishing other files on reported UFO sightings.

The government says it intends to repeal or amend up to 100 pieces of legislation which currently prohibit disclosure of information. It aims to replace them with provisions of a new Freedom of Information Act, passed in 2000.