London — Did Oleg Bitov come to Britain last year as a genuine Soviet defector? Or was he a Russian ''plant,'' whose subsequent return to Moscow was designed to embarrass the British governent and Western security authorities?
A year ago, when the foreign cultural editor of the Moscow weekly Literaturnaya Gazeta arrived in Venice and said he wanted to defect, he seemed genuine enough. He was brought to Britain and interrogated by security officers who decided that he should be allowed to stay.
Articulate in English, impressively briefed on Soviet and Western politics, Mr. Bitov explained that the shooting down of the Korean airliner by Soviet aircraft had been the last straw for him. He wanted to live and work in Britain, and very soon he was writing articles that were published worldwide. They attacked the Soviet system.
Bitov soon had a red Toyota car, a flat on the outskirts of London, two typewriters, and plenty of journalistic commissions. Then, a month ago, he disappeared.
This week he reemerged at a Moscow news conference claiming to have been abducted and tortured by British espionage officers.
The British government is angry - and puzzled by Bitov's behavior. Within hours of his reappearance in Moscow, the Soviet charge d'affaires in London was summoned to the foreign office and told that Bitov's remarks were ''absurd and offensive.''
Bitov's claim that he had been forced to write anti-Soviet articles as the price of staying in the West is being derided by British officials. But there are odd features about some of the defector's other comments in Moscow.
He gave the names, addresses, and telephone numbers of people he said were active in British intelligence and said he had been questioned in two ''safe houses'' in London.
There were strong indications that much of this information was accurate, but officials in London suggested that Bitov may have made it public to restore his own credibility with the Moscow authorities.
One of the people who met Bitov several times in the 10 months he spent in England is Alexander Lieven, former controller of the British Broadcasting Corporation's European services and a specialist on Soviet affairs.
''He was much more than a journalist. He made it clear that he had worked in the security field. He argued that he was fed up with the Soviet system which he considered dehumanizing and oppressive,'' Mr. Lieven said.
''But we may never know whether he was a genuine defector who was later blackmailed to return to Russia or, on the other hand, an astute double agent manipulated by the KGB (the Soviet secret police) to embarrass the British authorities,'' he added.
Lieven is inclined to believe that Bitov may have been sent to the West as a double agent but for a while decided that he would become a genuine defector. When this became apparent to the Soviet authorities, they may have found a way of forcing him to leave London and go back home.
There are signs that Bitov left Britain in a great hurry. His London bank account contained (STR)40,000 ($49,000) and he had ordered a word processor, with which he planned to write a book - ''Tales I could not tell'' - about his frustrations as a journalist in the Soviet Union.
Now Bitov claims he will write another book instead, describing alleged sufferings at the hands of Western intelligence.