Britain’s Prime Minister-in-waiting was pressed on the continuing diplomatic stand-off as he faced trade union members at Labour election hustings in Bristol.
“We want a peaceful settlement to the Iran issue,” he said. Asked directly if he could rule out military action, Mr Brown said simply that multilateral action and economic sanctions were the best way forward.
It was “totally wrong” for countries to defy the international community and to start stockpiling nuclear weapons, he added.
“What we don’t want is a situation where we move from North Korea to Iran to African countries, where we have no control. I think multilateral pressure is the right thing to do.”
The Government has been careful not to give unequivocal assurances since former Foreign Secretary Jack Straw said military action was “inconceivable” in November 2004.
Suggestions that US anger over his stance contributed to his removal from the job in a reshuffle last year were strongly denied.
Successor Margaret Beckett has chosen to say simply that there was “no intention” to mount an attack on the Tehran regime over its controversial nuclear programme.
Conservative leader David Cameron warned earlier in the week that although military action could have devastating consequences it should not be ruled out.
A poll by Open Europe has found that a majority of Britons (51%) would back military action, slightly below the EU average.
