ALIENS nearly brought the world to the brink of nuclear war, it was claimed at a UFO conference yesterday.

The crisis in the Ukraine was the most dramatic episode listed in a top secret dossier on the former Soviet Union's investigations into UFO.

It was exposed at the conference - at the Imperial College, London - by US investigator George Knapp, whose interviews with Russian military and scientific chiefs were shown in the UK for the first time.

In them, Colonel Boris Solokov, an expert in radio waves and radio astronomy at the Russian Ministry of Defence, told how, during the Cold War in the 1980s, a UFO presence nearly set off a nuclear disaster.

Col Solokov said that, on the night of October 4, 1987, dozens of soldiers working at a nuclear base in Usovoin the Ukraine saw up to five UFOs.

Reports from the base reached Solokov in the Kremlin, which des-cribed a ''spontaneous illumination of all displays on the control panel of the bases nuclear missiles.

The report said the top secret access codes to the deadly missiles had appeared spontaneously on screens at the base.

Col Solokov said: ''On October 5, 1982, I was ordered to go immediately to the Ukraine. The reason for the urgency was a report from the base commander to the chief of the general staff.

''The previous day, the base observed a UFO for four hours. At the same time on the control panel, they received an order to prepare the launch of the missiles.

''The lights lit up and the appearance of the launch codes meant the missiles were 'enabled'. Dozens of officers witnessed this.''

The incident helped push the Soviet authorities into a 10-year investigation of UFOs and aliens.

George Knapp, who has dismissed as hoaxes many alleged UFO incident, believes the Russians are telling the truth. ''It was a question mark for me at the very beginning, but now I am convinced,'' he said.

''These were not wide-eyed Ufologists. These were hardline, hardboiled Russian military figures secretly studying a potentially dangerous phenomenon.''