"The government has decided that we should accept the US request for assistance," Hoon told parliament on Thursday.
"A UK armoured battlegroup consisting of the 1st Battalion the Black Watch and supporting units will deploy ... to relieve a US unit for other tasks."
The previous day, British Prime Minister Tony Blair reacted to a barrage of criticism from politicians, analysts and national newspapers for considering the US request to redeploy British troops to Baghdad.
Insisting any decision was purely a military matter on Wednesday, Blair said sending the First Black Watch regiment to the Iraqi capital had "nothing to do with the American elections".
But even loyal Labour Party MPs voiced their scepticism.
Gerald Kaufman told parliament of the dangers "of being exploited politically in a closely fought US election".
His Labour colleague, Dennis Skinner, declared the redeployment would hand an "oxygen cylinder" to US President George Bush.
"I and many others ... do not take kindly to the idea that we are being engaged with President Bush and the Pentagon in order to bail them out."
Reflecting national sentiment, few papers have been positive about the redeployment.
"I and many others ... do not take kindly to the idea that we are being engaged with President Bush and the Pentagon in order to bail them out"
"His Country Needs You" declared the front page of Britain's The Mirror newspaper on Tuesday, with a mock-up of the famous Uncle Sam recruitment poster bearing Bush's face.
The popular perception, says Open University political analyst Geoff Andrews, is that Scottish troops would be redeployed nearer Baghdad to help Bush - not US soldiers.
"There is a complete breakdown of trust in the prime minister. Also, Bush is extremely unpopular and Blair has not convinced anybody that he is not just following the Bush line," Andrews said.
Amid the controversy over the proposed deployment, Britain's army chief General Sir Mike Jackson, on a visit to Indian-administered Kashmir, said the situation in Iraq for his country and other partners is "challenging".
But he is optimistic that the foreign forces and their local partners will cope with it.
Replying to a query on whether elections scheduled for January would be held on time, Jackson said on Thursday: "The situation in Iraq is challenging, that is so evident ... but both the interim government and the coalition are determined that the elections there are held on time and I very much hope they are."
Geoff Hoon has announced UK's
acceptance of the US request
US military commanders asked Britain to send a unit currently stationed in southern Iraq to the US-controlled sector further north on 10 October.
Bush has faced repeated accusations from Democratic nominee John Kerry that the White House is going it alone in Iraq.
"If the Americans want to go on the offensive, let them get on with it - by themselves"
Black Watch veteran
British ministers said yesterday that any redeployment would free up US forces and allow them to intensify their attacks on Falluja as Washington tries to quash all opposition ahead of elections in January.
Britain has some 9000 troops in Iraq, operating in the relatively peaceful area around the southern port city of Basra.
Sending British soldiers into the US-controlled sector carries a risk of higher casualties and would be politically sensitive for Blair. Sixty-eight British soldiers have been killed in Iraq, compared with more than 1100 US troops.
John Nicolls, a retired colour sergeant with 23 years experience in the Black Watch regiment, warns that the British casualty count is likely to escalate.
"The Black Watch are professional soldiers and they have never turned down an order and they never will ... but I know for a fact that the boys out there on the ground don't want anything to do with closer ties with the American forces.
"Of course they would have reservations about any change of policy but the families I have spoken to over recent days are convinced they're being caught up in politics, whatever the government might say," Nicolls said.
"They have kept the lid on Basra because they operate to a different ethos to the Americans ... if the Americans want to go on the offensive, let them get on with it - by themselves."
Additional reporting by Yusuf Jameel in Srinagar, Kashmir