The last major deployment of British troops to Afghanistan began on Thursday, the Ministry of Defence said, ahead of the withdrawal next year of Western forces.
Some 6,000 British troops will deploy to Helmand in southern Afghanistan in stages over the next six weeks, a ministry spokesman told AFP.
Britain currently has around 8,000 personnel left in Afghanistan but is set to cut this number to 5,200 by the end of this year.
The 87,000 NATO-led troops fighting Afghanistan's Taliban insurgency are due to pull out by the end of 2014.
Thursday's handover sees the 7th Armoured Brigade -- better known in Britain as the "Desert Rats", a division famed for their World War II exploits -- take charge at Britain's Helmand base from the 1st Mechanised Brigade.
Their main role will be to train Afghan security forces as well as pack up equipment, a ministry spokesman said.