By Peter Gould
BBC News Online correspondent
With war against Iraq now possibly days away, one protest group is planning its tactics.
CND says war will lead to widespread public protests
The Campaign for Nuclear Disarmament says it still hopes military action can be avoided, but it is now thinking about what to do in the event of war.
"Until now we have been putting all our energy into stopping the war," says CND chairperson Carol Naughton.
"But the reality is that it is looking more and more likely that it will happen."
The organisation - founded in 1958 to protest over Britain's development of nuclear weapons - says it has had a flood of new applications for membership as a result of the present crisis.
"The number of hits on our website has increased massively and we are having trouble coping with the number of people who want to join," says Ben Miller at CND's headquarters in London.
"It is a bit double-edged, but we do get more support at a time of crisis like this."
CND is calling on supporters to telephone or fax their protests to Tony Blair at 10 Downing Street and has published the numbers on its website.
Along with other anti-war groups, it is encouraging people to wear white ribbons for peace.
Carol Naughton: "Huge support" for campaign against war
Within hours of any military action, the organisation expects supporters to hold protest rallies outside town halls across the UK.
And within days, it intends to stage a mass demonstration close to Downing Street.
"We would expect huge support," said Ms Naughton, pointing to the one million people who marched through London last month.
"Even with a second resolution, I think there would be an enormous public outcry. Hundreds of thousands of people would come out to protest."
With doubts expressed about the legality of any military action against Iraq, CND has obtained a legal opinion from British experts on international law.
Their conclusion is that the second resolution, even if passed, would not authorise the United States and Britain to use force against Iraq.
And without a further resolution explicitly endorsing military action, they say any attack would be a violation of international law.
CND is now inviting all MPs who recently voted against the government to a meeting at Westminster this week to hear more about this legal opinion.
"We will be briefing MPs of all parties so they are in no doubt that this war would be illegal," says CND's lawyer, Phil Shiner.
"It does not matter if there are a thousand resolutions, unless there is specific authorisation for the use of force."
CND has already written to the prime minister, the foreign secretary and the defence secretary to warn them that they could be held accountable for any war crimes.
The organisation is setting up a tribunal of international lawyers to study the conduct of any military action inside Iraq.
CND argues that a definition of "war crimes" could include the use of weapons such as cluster bombs and fuel-air explosives, and high-level air attacks resulting in civilian deaths.
"There could be many more civilian casualties if there is indiscriminate bombing of Baghdad," says Mr Shiner.
CND members demonstrate against nuclear weapons in 1960
"Britain and the United States would be duty bound to take options to limit casualties."
There is also concern that any disruption of Iraq's electricity supply could stop the flow of clean water, leading to serious health problems.
CND says that any evidence of war crimes will be referred to the prosecutor at the International Criminal Court in The Hague.
Carol Naughton says she is finding growing support for the plan to hold political leaders to account for crimes against humanity.
"We want to be rid of Saddam Hussein and weapons of mass destruction," she says.
"But we do not want the people of Iraq to suffer."