SEVERAL Soviet arms shipments were supplied by the KGB to their ``Irish Friends'' in the Official IRA, according to intelligence files smuggled out of Russia.

The arms consignments were part of a plan by the KGB to create mayhem in Northern Ireland and in Britain by exploiting the campaign of terrorism that had been waged by the Marxist Officials in the early 1970s.

And the shipments continued even after the Officials had declared a ceasefire, according to the files revealed by former spy Vasili Mitrokhin to British security agency, MI6.

During the early 1970s the British security agencies were more concerned at the activities of the Officials rather than the Provisionals because of their Communist links and left-leaning policies. The Russians later used their contacts to introduce the Officials to ``helpful'' sources in North Korea and Czechoslovakia.

The Officials, who became known as the Stickies, used the leader of the Irish Communist Party Michael O'Riordan as an intermediary to negotiate the first shipment of arms, codenamed Operation Splash, in 1972.

In his memoirs, Russian president Boris Yeltsin said there was no evidence that arms were delivered to the Officials. But the Mitrokhin files showed that the Russian foreign intelligence service, the SVR, concealed the evidence in the KGB archives from Yeltsin.

The details of Operation Splash were approved on August 21, 1972, by the then KGB chairman and later Soviet president, Yuri Andropov. The arms two machine guns, 70 automatic rifles, 10 Walther pistols and 41,600 cartridges were all of non-Soviet manufacture to disguise their origin. They were transported to the Irish Sea under KGB supervision in an intelligence gathering vessel, the Reduktor, disguised as a fishing trawler.

The arms, in waterproof wrapping, were submerged to a depth of about 40 metres on the Stanton sandbank, 90 kilometres off the coast of Northern Ireland. They were attached to a fishing net marker buoy.

KGB experts examined the shipment before it left to ensure there was no trace of Soviet involvement, the Walther pistols were lubricated with West German oil, the packaging was purchased abroad by KGB operatives, and it was specified that the buoy should be Finnish or Japanese. The packages were picked up by a fishing vessel belonging to the ``Irish Friends'' although the crew were unaware of the contents.

Several more Soviet arms shipments were delivered to the Officials by similar methods. The man in charge of collection of the consignments was hardline terrorist, Seamus Costello, who later split with the Officials and formed the INLA and its political wing, the IRSP. He was subsequently murdered.

The Soviet arms are believed to have been used in bloody internal feuds involving the Officials and the INLA and subsequent clashes with the Provisionals.