Nick Hopkins reports for The Guardian:
Britain has rebuffed US pleas to use military bases in the UK to support the build-up of forces in the Gulf, citing secret legal advice which states that any pre-emptive strike on Iran could be in breach of international law.
The Guardian has been told that US diplomats have also lobbied for the use of British bases in Cyprus, and for permission to fly from US bases on Ascension Island in the Atlantic and Diego Garcia in the Indian Ocean, both of which are British territories.
The US approaches are part of contingency planning over the nuclear standoff with Tehran, but British ministers have so far reacted coolly. They have pointed US officials to legal advice drafted by the attorney general's office which has been circulated to Downing Street, the Foreign Office and the Ministry of Defence.
This makes clear that Iran, which has consistently denied it has plans to develop a nuclear weapon, does not currently represent "a clear and present threat". Providing assistance to forces that could be involved in a pre-emptive strike would be a clear breach of international law, it states.
"The UK would be in breach of international law if it facilitated what amounted to a pre-emptive strike on Iran," said a senior Whitehall source. "It is explicit. The government has been using this to push back against the Americans."
Sources said the US had yet to make a formal request to the British government, and that they did not believe an acceleration towards conflict was imminent or more likely. The discussions so far had been to scope out the British position, they said.
"But I think the US has been surprised that ministers have been reluctant to provide assurances about this kind of upfront assistance," said one source. "They'd expect resistance from senior Liberal Democrats, but it's Tories as well. That has come as a bit of a surprise."
The situation reflects the lack of appetite within Whitehall for the UK to be drawn into any conflict, though the Royal Navy has a large presence in the Gulf in case the ongoing diplomatic efforts fail.
The navy has up to 10 ships in the region, including a nuclear-powered submarine. Its counter-mine vessels are on permanent rotation to help ensure that the strategically important shipping lanes through the Strait of Hormuz remain open.
The Guardian has been told that a British military delegation with a strong navy contingent flew to US Central Command headquarters in Tampa, Florida, earlier this summer to run through a range of contingency plans with US planners.
The UK, however, has assumed that it would only become involved once a conflict had already begun, and has been reluctant to commit overt support to Washington in the buildup to any military action.
"It is quite likely that if the Israelis decided to attack Iran, or the Americans felt they had to do it for the Israelis or in support of them, the UK would not be told beforehand," said the source. "In some respects, the UK government would prefer it that way."