Anti-war protests have been held across the world to mark the fifth anniversary of the Iraq invasion.

The war has claimed the lives of 175 British service personnel, nearly 4,000 Americans, 210 journalists and media assistants, and an estimated 90,000 Iraqi civilians.

Campaigners including the Stop The War Coalition (STWC), CND and the British Muslim Initiative staged a vigil outside Downing Street and delivered a letter to Prime Minister Gordon Brown demanding a public inquiry into the conflict and calling for troops to be brought home.

They also urged people to hold a minute's silence in remembrance of the civilians and soldiers who have died in the conflict.

The letter to Gordon Brown describes the Iraq war as "disastrous" and calls for March 20 to be declared International Peace Day.

At present there are around 4,000 British troops in Iraq, the majority based in Basra.

Britain remains America's "closest ally" in Iraq, according to US Defence Secretary Robert Gates.

Meanwhile, US President Bush used the fifth anniversary of the Iraq War to say removing Iraqi dictator Saddam Hussein from power was the right decision.

The war on terror is "a fight America can and must win" and Iraq is "the place where Arabs joined with Americans to drive al-Qaeda out", he said during a key speech at the Pentagon.

"In Iraq, we are witnessing the first large-scale Arab uprising against Osama bin Laden, his grim ideology, and his terror network," he said, adding that success there was "undeniable".

Both potential Democratic nominees, Barack Obama and Hillary Clinton, support a withdrawal of US troops from the war.

Mr Obama has attacked republican nominee John McCain for "embracing the failed policies of the past" and for "refusing to learn from the failures of the Bush years".

© Independent Television News Limited 2008. All rights reserved.