London — A scowl furrows his brow. His face showing the strain of living for years under threat of assassination, Muammar Qaddafi listens. The Libyan leader tries to concentrate for a moment on the questions newsmen fire at him at a Tripoli news conference. His thoughts seem far away.
Even as Colonel Qaddafi accuses Britain of framing his former emissaries in London for the murder of a British policewoman to provoke Britain to break ties with Libya, his eyes seem to look beyond the TV cameras in the security-cordoned room.
Isolated from neighbors whom he has alternately helped with money and arms and harmed with conspiracies, Qaddafi is a leader haunted by his past, say former intimate friends and associates. They say his thoughts are often filled by memories of disastrous military adventures, such as his support for Ugandan dictator Idi Amin, or his present encounter with the French-backed regime in neighboring Chad.
Perhaps other specters cross his vision: shattered plans for Libya's union with Egypt, Sudan, Tunisia, Algeria, and even Syria.
The TV cameras show Qaddafi return from his reverie. He faces the reporters again and offers France a carrot: mutual withdrawal of French and Libyan troops from Chad. Then he wields a stick against Britain: a threat to again aid guerrillas from the outlawed Irish Republican Army.
The troubled leader on the television screen seems to have little in common with the idealistic and unknown young man this reporter first met in Tripoli in 1969, only days after he and a baker's dozen of like-minded other young lieutenants had overthrown the Western-protected King Idris.
Qaddafi is zealous, puritanical, and conspiratorial. His moods vacillate between elation and depression, although he is still charged with a sense of mission. That mission, he often said in so many words, was to continue the struggle for Arab unity and liberation begun by his idol, Egypt's late President Gamal Abdel Nasser.
Now, Qaddafi's Libyan opponents say - with much evidence to support them - Qaddafi's direct personal hand on Libya's tiller is partly replaced by a kind of revolutionary directorate. Its members are young zealots, scarcely known even in Libya. Qaddafi, denying that he is chief of state, can approve or disavow their acts and decisions as he chooses.
Qaddafi's opponents say this inchoate system breeds chaos.
''Opposition is sweeping Libya like a growing storm,'' says Muhammad Magarief , once a financial controller, who is shocked by Qaddafi's reckless spending of Libya's oil wealth on foreign adventures.
Abdul Hamid Bakkoush, who served as prime minister for King Idris, agrees. He adds that overthrowing Qaddafi, protected as he is by loyal tribesmen and East German security guards, may not be easy.
Many close observers wonder about Qaddafi's sanity. Newsmen in Libya recently reported that he is said to depend heavily on tranquilizers, and that he acts like a man in physical danger.
The confusion evident in Qaddafi's thinking and utterances is matched by apparent incoherence in his policies. Dreams he had as a student at the Libyan military academy centered on Arab unity and liberation. But with each foreign misadventure, these dreams have faded.
By the time the United States suspended diplomatic ties with Libya in 1981, Qaddafi had begun to lash out at neighbors and had alienated friends, including US and other Western intelligence agencies, which at first felt his anticommunist, Muslim zeal deserved protection.
Qadaffi's targets had included Egypt, Sudan, Tunisia, and Morocco. Then his tactics began to change. He indulged in a series of on-again, off-again flirtations with ''reactionary'' regimes, as he had called them, like those of the Moroccan and Saudi Arabian kingdoms.
Qaddafi first offered, then withdrew, help for Moroccan King Hassan's adversaries, the Polisario guerrillas fighting Morocco for control of the former Western Sahara. Qaddafi kept up sporadic pressure on Tunisia. He has even turned against Algeria, which he once termed a ''revolutionary sister state.''
Recently he has financially supported an Islamic fundamentalist group headed by Ahmed Ben Bella, Algeria's first president after independence, now considered in Algeria a subversive nuisance to President Chadli Benjedid's government.
In the Mideast, Qaddafi helps various radical Palestinian guerrilla groups, but spurns as an enemy the mainstream Palestine Liberation Organization chairman , Yasser Arafat. In Lebanon, he finances groups like the Sunni Muslim Murabitoun militia in west Beirut. This has proved an embarrassment to Qaddafi's ally, Syria, in its recent efforts to pacify Lebanon.
Recently, Qaddafi's chief aide, Maj. Abdul Salam Jalloud, has been seeking better understanding with another ally of circumstance, Iran's leader, Ayatollah Khomeini. Despite Qaddafi's paradoxical support for non-Arab Iran against Arab Iraq, Khomeini has so far not forgiven Qaddafi for the still unexplained disappearance in Libya in 1978 of the charismatic Iranian-born leader of Lebanon's Shiite Muslims, Imam Musa Sadr.
At home, even Qaddafi's ''parallel government'' by people's committee has turned against him, as oil income declines and ill-starred economic experiments weaken Libya's once-opulent welfare state system.
Early this year, some people's committees - local groups of Libyans at their places of work - opposed Qaddafi's proposals for compulsory military training of women and for changes in family and educational law.
An angry Qaddafi sacked the leadership of the General People's Congress, his real cabinet. More radicals were brought in. He was shrewd enough to appoint as new foreign minister Ali Treiki, a capable career diplomat recalled from his post as Libyan permanent representative to the United Nations.
Qaddafi's Libyan opponents abroad anticipated new terror against them comparable to or worse than that in 1980 when he created an ominous new ''ministry for external security'' last winter.
In February, four key young pro-Qaddafi zealots took over the London ''people's bureau,'' or embassy. Police here say it was these zealots who committed bombings and made threats against anti-Qaddafi Libyans in London and Manchester in March.
Then, on April 16, student revolutionary committees in the Libyan capital hanged two fellow students in public. This did much to trigger the anti-Qaddafi demonstration in London, which led to the murder of a London policewoman by shots from the embassy the next day.
Seasoned European and Arab analysts here believe the Reagan administration's desired campaign of Western pressure against Qaddafi would be counterproductive. They doubt that European trade sanctions will be enacted against Libya or that, if enacted, they would change Qaddafi's policies. Europeans might tacitly approve covert CIA operations against Qaddafi, but they are unlikely to join them.
What may someday be tested is how far the East German security men and the 2, 700 or so Soviet military advisers in Libya would go to defend Qaddafi. He has never been willing to sign a friendship or alliance treaty with Moscow. Whether he will make good on recent threats to grant the Soviets air or naval base facilities against the West in the eastern Mediterranean also has yet to be proved.
Here, too, incoherence may prove the future theme of Qaddafi's thoughts, words, and deeds.