London — Britain yesterday decided to send four Royal Navy minesweepers to the Persian Gulf to help with the escorting of British-registered tankers. In a new policy, the Ministry of Defense said additional mines had been found in the past 48 hours and that a ``new situation'' thus had developed in Gulf waters. Two weeks ago Prime Minister Margaret Thatcher, with other Western European leaders, refused President Reagan's request to provide British minesweepers to protect American-flagged Kuwaiti tankers passing through the Strait of Hormuz. That decision, which shocked United States officials, has been hotly debated in Britain.
Mrs. Thatcher has not reversed her policy toward the initial American request. However, until now, Mrs. Thatcher saw no need for a minesweeping contingent to help other British naval ships in the area.
Her defense secretary, George Younger, said Tuesday the Royal Navy sweepers would accompany British-flagged ships. After the American-owned supertanker, Texaco Caribbean, hit a mine on Monday while passing through the Gulf of Oman, Mrs. Thatcher ordered an urgent policy reappraisal.
Her advisers told her the many British-owned tankers that pass through Gulf waters every week would be at severe risk if mines had been laid over such a wide area.
After quick checks with senior ministers, many of whom are on vacation, the prime minister ordered a flotilla of four Hunt-class minesweepers, together with a support ship, to sail for the Gulf as rapidly as possible. The four British minesweepers are expected to arrive in Gulf waters in mid-September.
Yesterday, Gulf shipping sources described the latest discovery of mines in the the area as a new threat to international oil lanes.
The Royal Navy has excellent minesweeping equipment, which is why President Reagan wanted its services in the Gulf.
Defense experts in London said that although the minesweepers technically would accompany only British-flagged ships, they could be expected to work closely with US Navy ships in the Gulf area.
One expert at the International Institute of Strategic Studies said: ``Ever since the Gulf war began, Western navies in those waters have had a close working relationship and have grown used to work sharing. One can assume that the same will apply in this new situation.''
[France also announced Tuesday it would send minesweepers to the Gulf to protect French-registered tankers.]