The 40,000-strong London demonstration began with a rally that filled Trafalgar Square.
Lindsey German, national convenor of the Stop the War Coalition, told the crowds, “Five years on, we’re still marching because they’re still occupying.”
To loud cheers Tony Benn agreed, saying, “Parliament represents the past – the streets represent the future.”
In both London and Glasgow marches were buoyed with new and younger demonstrators.
Sixth form student Sameeyah came with a delegation from Greenford High School in Ealing.
She told Socialist Worker that while she had been on many anti-war demonstrations before, half of her group had never been on a march.
She said, “I told people to come because being on a demo gives you a chance to articulate your feelings about what is happening in Iraq, Afghanistan and Palestine.
“A group of us got together and decided to make our own anti-war banner, though we had to get my mum to sew it for us.”
It was also a first demo for west London law student Saima Haq. She said, “I have very strong opinions about the world but I don’t feel that I know enough – you see snippets on the news but don’t get the full picture.
“I’ve come here to educate myself. My family comes from Pakistan. When Benazir Bhutto was killed, it made me take stock of what is happening. It shows how the war is spreading.”
Saima came with her friend Shabana who had been on the anti-war demonstration five years earlier. She said, “There is a campaign of hate building up against Iran.
“We have to tell the government that we marched five years ago and the same anti-war feeling is still here today.”
The presence of thousands of trade unionists also boosted the marches, with many pointing to the way public services are being squeezed while there appears to be endless money for war.
“It’s very important for trade unionists to be part of this campaign,” said Paul Robertson, a Unison union shop steward in Tower Hamlets council, east London.
“Millions of workers are facing a 2 percent pay cut this year, yet we’ve just heard that the cost of the war has doubled.
“Our branch has always supported the Stop the War Coalition and this is the 12th anti-war demonstration we’ve been on.”
Banners from teaching unions in all sectors of education were particularly well represented on the London march.
In the face of a recruitment crisis, the military has been attempting to attract students by running stalls in colleges.
Amanda Sackur, a union rep at London Metropolitan University, said, “Working people bear the brunt of the government’s war policy, and it is the poorest that are being conned into joining the army.
“The unions must be involved in the fight against the war.”
Demonstrators from all backgrounds shared a common anger with Gordon Brown, who on taking office had attempted to put distance between himself and Tony Blair.
Dr Azzam Tamimi from the British Muslim Initiative spoke of the horrors rained down by Israel on Gaza and the people of Palestine in recent weeks.
He denounced Brown’s government’s complicity with Israeli war crimes.
“We were promised that Brown would be better than Blair, but he is just as cowardly.”
“There is something inherently wrong with this political system and we need to change it for good.”
Over 5,000 people marched through Glasgow, with a strong turn out from the trade unions, students and Scotland’s Muslim community.
School student Amicima said she had joined the protest to “show support for the Palestinians, to stop these horrible massacres, and because I am concerned that the US might now attack Iran”.
At the rally on Glasgow Green Kenny Ross, the regional secretary of the Fire Brigades Union, pointed out that the cost of war is now £3.5 billion a year.
“People like you and me are paying for that,” he said. “And Gordon Brown is the man who wrote the cheques for the last five years. Public sector workers are losing their jobs and we face paltry pay rises as the cost of living spirals.”
Addressing the marchers, Scottish National Party (SNP) deputy first minister Nicola Sturgeon called for troops to be brought home and for those responsible for taking us to war to be brought to account.
She pointed out that something had changed since the Iraq invasion. “People across Scotland – and now the party of government in Scotland – say no to this illegal war,” she said.
Anti-war activists were cheered by an SNP motion, tabled two days earlier, which attacked the war and backed Rose Gentle, a founder of Military Families Against the War.