London — Britain's relations with Iran are at their lowest ebb since the overthrow of the Shah. This is seen as the result of several provocative moves by revolutionaries loyal to Ayatollah Ruhollah Khomeini.
Recent developments confirm fears held in Whitehall that Iran's contacts with the outside world are being allowed to sour over a broad diplomatic front. Dealings between Britain and Iran have been generally cool since the revolution, but the storming of the Iranian Embassy in London three months ago by British troops tended to improve the relationship.
But now the diplomatic atmoshpere between the two countries appears to be going the same way as that between Iran and the United States, with revolutionary students contributing largely to the deterioration.
Adverse developments include:
* Student demonstrations in central London that led to the arrest of 68 Iranians who refused to give their names. Magistrates had no alternative but to keep them in detention. The detainees went on a hunger strike and agreed to end it only if a senior Iranian diplomat accused the London police of "unjust and discriminating behavior."
* The detention in Isfahan by the revolutionary prosecutor of the former secretary of the Anglican Bishop of Iran. Miss Jean Waddell, a member of the Church Missionary Society, voluntarily traveled from Tehran to Isfahan, seeking to arrange an exit visa for herself. She was seized and held in custody indefinitely on a vague charge of spying. The British Foreign Office has issued a strong protest.
* A steady build-up of political demonstrations outside the British Embassy in the Iranian capital. Thousands of demonstrators have been accusing Britain of being anti-revolution, and say he detained students in London have been victims of police brutality.
* Continuing expulsion from Tehran of British news correspondents. The latest to receive marching orders is BBC correspondent Alex Brodie. He was accused of "negative reporting." Mr. Brodie was one of a tiny number of British newsmen trying to keep open lines of communication between Tehran and London.
Whitehall officials say there is a depressing similarity between Iranian treatment of Britain in recent weeks and Tehran's attitude to other nations. They detect a mood of heedlessness, with the government at a loss to control revolutionary elements seemingly determined to pick quarrels with allegedly unfriendly countries.
The case of Miss Waddell has proved particularly distressing and forms part of a systematic attempt to link the Anglican Church in Iran with alleged spying activities.
Last May, Miss Waddell was wounded when police burst into her flat firing automatic weapons. She was till recovering from her wounds when she journeyed to Isfahan to answer questions from a revolutionary court.
The authorities there seized her and released a letter, said to have been written by the British ambassador, thanking the Anglicans for assisting with "espionage activities."
The letter -- not on embassy note paper -- was written in broken English and carried a false ambassadorial signature.
The Foreign Office in London bitterly dismissed it as a clumsy forgery. But there were fears that Miss Waddell had become caught up in a complex political vendetta. Attempts to secure consular access to her had no immediate effect.
In recent months Britain has gone to a lot of trouble to skirt around the worst excesses of the revolutionary ferment in Iran.
It was reluctant to apply rigorous trade and economic sanctions against Iran. The storming of the Iranian Embassy in London in May by Special Air Service troops drew a letter of thanks to Prime Minister Margaret Thatcher from Iranian President Abolhassan Bani-Sadr.
Now, however, relations are in disarray. There are moves in preparation to scale down the number of diplomats in the British Embassy in Tehran. One official declared: "We are still trying to avert a total collapse in the relationship. President Bani-Sadr seems unable to bring significant influence to bear on the Ayatollah's followers, and relations between Britain and Iran are proving a major casualty of revolutionary activity."