LONDON - Britain's leaders are discussing how the country would respond to any military confrontation between Israel and Iran, including the possible involvement of its navy, the BBC reported Wednesday.

As six world powers began talks in Baghdad with Tehran on its nuclear programme, the BBC said the National Security Council, which is chaired by Prime Minister David Cameron, had met last week to discuss the issue.

It had discussed "not just the possibility of a military confrontation but what role, if any, Britain might play and whether any involvement would be legal", the report said.

Government lawyers have been examining the legality of any British involvement, "ranging from British diplomatic support for Israel through to the possible involvement of the Royal Navy in the region", the BBC reported.

Senior ministers on the council were told that if talks with Iran fail and Israel attacks its nuclear facilities, this might trigger a wider war in the Middle East, the report said, without citing sources.

Iran might respond not just by attacking Israel but also by closing the Strait of Hormuz, a key transit route for global oil supplies, the council -- which co-ordinates responses to national security threats -- was told at a meeting in London last week, said the report by the BBC's political editor.

Top officials from the United States, Russia, China, Britain, France and Germany began talks with Iranian leaders in the Iraqi capital on Wednesday, aiming to persuade Tehran to suspend sensitive nuclear work.

Leaders in Israel, widely believed to be the Middle East's sole if undeclared nuclear armed state, believe the country's existence could be threatened if Iran develops atomic weapons and have repeatedly said all options are on the table.

A former chief of Britain's defence staff, Air Chief Marshal Jock Stirrup, warned parliament's upper house last week that Iran could retaliate against Britain if attacked by Israel, meaning London must be prepared to respond.

The previous Labour government faced a backlash over its participation in the US-led invasion of Iraq in 2003 and presence there until 2011, including doubts over whether the military action was legal under international law.

Current junior coalition partners the Liberal Democrats, who are partnered with the Conservatives, opposed the war in Iraq and are insisting any future action be clearly within international law, the BBC report said.

Cameron told a parliamentary committee in March: "We think that military action against Iran by Israel would not be the right approach. We've said that both publicly and privately to the Israelis."