Menzies Campbell: Brown's reply could have been written by Blair

In Iraq British troops are dying at a rate not seen since 2003, the year the war began. More of our soldiers have been seriously or very seriously injured this year than in any other since the conflict strarted.

These grim, statistics will be all too familiar to the 5,500 British troops now holed up at Basra airbase. In private, and occasionally in public, military opinion is of the view that the British mission in Iraq has failed and only serves to exacerbate rather than calm hostilities. According to one off-the-record briefing, 90 per cent of insurgent attacks are now directed one way – at British forces. As Gen Sir Richard Dannatt said last year, the consent that British forces once relied on "has largely turned to intolerance". Last week Sir Michael Rose, an outspoken critic of the war, said that Iraq was an "unwinnable" war.

On 16 August I wrote to Gordon Brown demanding an urgent reappraisal of the government's strategy in Iraq and Afghanistan. I called for a framework for the withdrawal of troops from Iraq, enabling reinforcements to be directed to the NATO mission in Afghanistan and avoiding the costly duplication of fighting two major operations simultaneously.

Like many others, I hoped the Prime Minister would be ready to signal a break from the failed policy of his predecessor. I hoped he would take a decision that reflected the best interests of Britain and our forces. I should not have expected such a radical departure. The Prime Minister's response could have come straight from the pen of Tony Blair. He made much of Britain's international commitments to Iraq under UN resolutions. Yet the decision to withdraw will be for the British government alone. Although the UK has international legitimacy for its current role, this does not, in itself, have any bearing on whether it is the right policy for Britain (or Iraq for that matter).

The fact is that British forces no longer credibly provide "overall security" as the Prime Minister claims. As for other activities such as training and mentoring the Iraqi army and police, these roles could be pursued under NATO or UN auspices.

Neither is the British role in protecting American supply routes enough to bind British troops to Iraq indefinitely. As Prof Michael Clarke, Director of the Royal United Services Institute, remarked recently, "the US operation is self-sufficient. The US would never let themselves become dependent on others."

In persisting with his predecessor's arguments, the Prime Minister may hope to keep the issue low down the news agenda. But the arguments he relies on are being steadily eroded by the facts on the ground.

The rising casualty rates have coincided with the British forces' pull back to a single base at the airport at Basra. British forces are targeted with up to 10 mortar or rocket attacks every day. The tragic deaths of three RAF servicemen, killed at the airbase by rocket attack in July, confirm the vulnerability of the troops' position at Basra. The increasingly fragile position of British forces in Iraq is an issue of immediate concern to the British public and must be at the top of his agenda.

Neither can the Prime Minister overlook the critical strain placed on British forces by the demands of fighting in two theatres. Equipment and key "pinch-point" trades within the forces are suffering badly. Gen Dannatt among others has warned about the impact of overstretch on the capacity of the armed forces to deliver. There is a shortage in critical staff such as bomb disposal experts and helicopter pilots. How long can the Government run from these facts before they really bite?

Mr Brown cannot ignore the public outcry over the state of the military covenant. The state of forces' accommodation, combined with the stress on their personal lives of longer operational commitments must be addressed. So far, the Prime Minister has avoided tackling the issue head on.

The final consideration which will most likely bring the issue to a head in the UK is the debate in Washington. As the US Presidential elections gear up, Iraq will take centre stage. The British public cannot be denied their own say in the debate, as under Tony Blair's premiership they were denied an inquiry into the government's case for war with Iraq.

The Prime Minister's response has done nothing to alter my view that Britain must set a timetable for withdrawal from Iraq. I asked him if our brave young men and women are risking their lives only to show solidarity with the Bush administration. Mr Brown did not respond directly, but the paucity of his argument suggests that the attitude of the US is a significant concern. British interests must direct our government's decisions.

The writer is leader of the Liberal Democrats