No measures were ruled out against Iran by Premier Minister Gordon Brown Monday.
Brown said it was possible to make Tehran meet its international obligations by diplomatic means, including sanctions if necessary, but refused to rule out the use of force.
"What I am prepared to say is that we take very seriously what Iran is proposing and we are prepared to use the methods that we have used in diplomacy and sanctions to deal with this problem, and I do not rule out anything," Brown said.
Brown once again accused Iran of arming militants in Iraq, saying Tehran was "breeding violence and supporting terrorism and causing loss of life".
Iran has always denied it is pursuing the development of a nuclear weapon, saying its program is solely aimed at power generation.
British Foreign Minister David Miliband has called for continued dialogue with Iran over its nuclear program and its intentions in Iran.