THOUSANDS of British troops will have to remain in Iraq until at least 2008 - two years later than the government intended, The Scotsman has learned.
Senior military sources say the army has been told to plan to keep a brigade-sized garrison of more than 7,000 troops in Iraq for four more years or more.
The planned extension in deployment has been prompted by the continuing Iraqi insurgency and the inability of local security forces to control the country without US and British troops.
The news could not have come at a worse time for Geoff Hoon, the Defence Secretary, who appears determined to press ahead with his plans to cut four infantry battalions and disband the army's Scottish regiments.
One senior army officer said: "When the requirement to keep troops in Iraq until 2008 filtered back to the army, everybody started wondering how we were going to do this."
Army high command had hoped to start cutting the 8,000-strong Iraq garrison at the end of the year, with the aim of pulling out completely by late 2006.
Under the first phase of the plan, two infantry battalions deployed to train Iraqi security forces in the summer were not to have been replaced when their tours end in December and January.
But Mr Hoon has already had to backtrack on this. Last month, the Defence Secretary announced that one of the battalions is going to be replaced next month by the 2nd Battalion the Princess of Wales' Royal Regiment.
Active consideration is also being given to reinforcing it with the Edinburgh-based Royal Scots, which has been placed on "ten days' notice to move".
Training the Iraqis is taking longer than expected and forcing the UK and the US to keep their troops in the country.
The US has already announced it will boost its troop strength to 150,000 during the first half of next year to provide security during and after the January elections.
Meanwhile, the insurgency is continuing unabated.
Yesterday, gunmen ambushed a bus full of Iraqis working for the US military, killing 17 civilians and wounding another 13, near Tikrit.
A car bomb and a gun attack also killed four members of the Iraqi security forces elsewhere in northern Iraq.
The violence was the latest in a string of deadly attacks targeting Iraqi forces and others allied with the US military that have killed at least 68 Iraqis since Friday.
General John Abizaid, the United States' top commander in the Middle East, warned this weekend that the Iraq's home-grown forces aren't yet up to the task of ensuring secure elections, necessitating the planned increase in US troops.
He said: "It had been our hope that we would be able to have a combination of increases that mainly were Iraqi troops' increases. And while the Iraqi troops are larger in number than they used to be, those forces have to be seasoned more, trained more.
"So it's necessary to bring more American forces."
While attention is currently focused on next month's Iraqi national assembly election, British and American military commanders are aware that this is only first of a series of elections in 2005 that will require a heavy security presence.
This will culminate in December 2005 in the first governmental elections under the new constitution, and a build-up of troops for that key event has already begun.
It has emerged that more Scottish soldiers will also be heading to Iraq in the autumn of 2005, when the Highlanders will deploy to Basra with the 7th Armoured Brigade, the Desert Rats, which has been alerted to be in Iraq in time for the December election.
The demand for troops in Iraq means the MoD may not be able to meet its commitment to provide troops to the NATO garrison in Afghanistan. NATO has asked the UK to increase its force by more than 2,000 to tackle to heroin trade outside the capital, Kabul.
By Tim Ripley and William Lyons