THE reports on British arms sales to Iran that appear in this paper today, following similar disclosures in the Independent on Sunday, make disturbing reading. In spite of an official embargo, British arms were reaching Iran during its war with Iraq in the Eighties, possibly with the knowledge or connivance of officials at the Ministry of Defence. The first question that needs clearing up is whether a secret British foreign policy was operating under which these sales were authorised contrary to declared policy. The evidence is not conclusive. Given the sophistication of the international arms trade, it remains possible that officials were not fully aware of where the arms were going. If that is the case, the accusation is one of gross negligence. Otherwise it is one of double-dealing and deception. Whatever the truth, there is no reason now why the matter should not be fully investigated and the answer made public.

There would have been defensible reasons for selling arms to Iran in that period. No reasonably far-sighted person would have wanted Saddam Hussein, who was the aggressor, to win a decisive victory. Iran was much larger and strategically more important as a future friend, and one of the main sources of militant Islamic ideology. Any influence the West could gain there could only be useful. Iran also held the key to the release of Western hostages in Lebanon. These considerations led the United States into the secret and contradictory policies of 'Irangate'. If Britain was tempted down the same road, it could at least explain why.

Historical truth is not the only reason for investigating the issue. International arms sales are a threat to peace. Too many of them take place in a murky area of secrecy and deniability. Even when they are open, they are extremely difficult to control. Governments are too easily seduced into believing they will buy political influence and too weak to resist pressures from manufacturers, particularly in times of recession. Vaclav Havel, when he became president of Czechoslovakia, was dismayed to find that a whole town would be put out of work if he stopped a sale of tanks to Syria. He was forced to put his ethical principles aside. Western governments are no less vulnerable.

There is no shortage of ideas for curbing the menace. Plans to have all arms sales reported to the United Nations are already developing. Arms control inspections are becoming more intrusive. The Japanese and others want to link aid to the size of the recipient's defence spending, cutting help to those who squander their resources on arms.

The solutions to the problem lie mainly in the hands of the five permanent members of the United Nations Security Council. They are supposed to be responsible for global security, yet they supply around 90 per cent of the world's arms, a conjunction that would puzzle a rational Martian.

Until they can learn to co-operate in more responsible policies, and systematically shift their economies away from excessive dependence on defence contracts, they will continue to exacerbate the regional tensions they simultaneously deplore. Already a new arms race is under way in the Middle East in spite of agreements on restraint. Britain should now use the impetus provided by the latest revelations to press for real change in these dangerous habits.