TEHRAN - A bill to downgrade Iran's relations with Britain got final approval on Monday, state broadcaster IRIB reported, a day after parliament approved the measure compelling the government to expel the British ambassador.

"The members of the Guardian Council, after examination of the plan, have approved it unanimously," Abbasali Kadkhodai, spokesman for the council, was quoted as saying on IRIB's website.

The exceptionally rapid approval from the Guardian Council, a panel of 12 clerics and jurists who judge whether legislation is Islamic, reflects the urgency with which Iran is treating its reaction to punitive sanctions announced by Britain last week.

Britain acted following a November 8 report by the UN nuclear watchdog citing intelligence indicating that Iran has worked on designing an atomic bomb. Iran says the intelligence is forged and that its nuclear energy programme has wholly peaceful aims.

Passed by legislators who chanted "Death to England" on Sunday, the law is retaliation for London's decision to ban British banks from dealing with Iranian ones, including the Central Bank of Iran.    

Members of parliament said Iran would take similar action against any other countries that follow suit.  

European Union foreign ministers are due to meet on Thursday to approve new sanctions that could cut financial links and ban oil imports from Iran over suspicions that it is trying to develop nuclear weapons.