A serving soldier facing a court martial for refusing to return to Afghanistan called on Britain to withdraw all troops from the country at an anti-war demonstration in London yesterday that attracted 5,000 protesters.

Lance Corporal Joe Glenton, 27, of the Royal Logistic Corps, said the presence of British forces in one of the world's poorest countries was making the situation worse. "It is distressing to disobey orders, but when Britain follows America in continuing to wage war against one of the world's poorest countries, I feel I have no choice," he told anti-war protesters at Speakers' Corner in Hyde Park.

"Politicians have abused the trust of the army and the soldiers who serve. That's why I am compelled and proud to march with the Stop the War Coalition."

The father of a soldier killed in Iraq, who recently refused to shake hands with Tony Blair, also attended the march. Peter Brierley, 59, whose son, Lance Corporal Shaun Brierley, was killed in Iraq in 2003, recounted how he told the former prime minister at a memorial at St Paul's Cathedral, London, that he had blood on his hands and that one day he would have to answer for what he had done. His son was 28 when he was killed.

"They are not doing any good while they are over there. They need to leave the country to sort itself out," said Brierley. "While the British troops are there they are actually attracting more insurgents who are coming in to fight."

The country's oldest anti-war demonstrator also joined the march. Londoner Hetty Bowyer, 104, told the crowd: "I march because I can see no reason for further killing. I have walked on every march against us going to war. At my age there is not very much I can do, but while my legs can carry me I am going to march."

Central London was brought to a temporary standstill as the protesters made their way to Trafalgar Square. Glenton, from Norwich, led thousands of protesters as they snaked through the capital.

Meanwhile, the battalion that lost more men than any other during the most recent deployment to Helmand province arrived back home yesterday. Troops from 2nd Battalion The Rifles returned to Northern Ireland after losing 13 men and having dozens injured during their six-month tour in and around Sangin, the deadliest place for British soldiers in Helmand.

The battalion's commanding officer, Lieutenant-Colonel Rob Thomson, described how the Taliban had encircled Sangin with roadside bombs and improvised explosive devices (IEDs), making movement fraught.

Thomson said: "The enemy has planted IEDs in a greater number than ever before. It has been a hard battle, but the riflemen have found hundreds of IEDs across the area of operations. It is difficult to describe accurately the intensity of this fight."