Amid unprecedented Commons scenes Robin Cook has told MPs that he could not support a war without international support.

Warning that Tony Blair was "going out on a limb" to support the US he said that war had "neither international agreement nor domestic support".

Whilst he applauded the "heroic efforts" of the prime minister, Cook said that "we cannot pretend that getting a second resolution was of no importance".

Contrasting the UK's stance on Iraq to that of Israel he asked why there "was one rule for the allies of the US and another for the rest".

"Why is it now so urgent that we should take action to disarm a military regime that has been there for 20 years and that we helped to create," he said.

In an attack on George W Bush he warned that Britain would not have been asked to commit troops if the Democrats had won the last presidential election.

Warning that the UK is isolated in the EU, NATO and the United Nations he said that Britain had lost the argument.

"The US can afford to go to war. But Britain is not a superpower," he warned in a personal statement to MPs.

The former Commons leader said he had been given no option but to resign from the Cabinet.

Flanked by former Cabinet colleagues Chris Smith and Frank Dobson, Cook said that "the threshold for war should always be high".

But he dismissed claims that he was turning his back on British troops.

"It is false to argue that it is only those who support war support our troops," he told MPs.

As he concluded the statement he received sustained applause from many in the House.