A body found in Afghanistan is thought to be that of a kidnapped British lorry driver, Foreign Office minister Kim Howells has said.
David Addison's convoy was ambushed in the Farah region
David Addison, who had been working on a road project, was abducted in the west of the country on Wednesday. His body was found on Saturday morning.
Mr Howells blamed the Taleban saying the group had "committed an atrocity".
The Taleban claimed responsibility for the killing, saying that it believed the Briton was a "military official".
Abdul Latif Hakimi, a spokesman for the Taleban, said six hostages, including a UK contractor had been shot following a decision by a Taleban council, the Afghan Islamic Press (AIP) reported.
He said the decision to "execute" the British worker was also taken because of Britain's invasion of Afghanistan.
"It has killed many civilians in Afghanistan and has bombed many regions," he said.
Mr Addison's family were said to be "very distressed and upset".
A statement read by Mr Howells on their behalf of Mr Addison's family said: "David was a very loving husband and father and he'll be sorely missed.
"We ask that our privacy is respected as we come to terms with this sad news."
Mr Howells condemned the Taleban for kidnapping Mr Addison and killing three of his Afghan police guards when the convoy they were travelling in was ambushed in the Farah region.
Mr Addison's Afghan interpreter was also reported kidnapped.
It is not yet known precisely how and when Mr Addison died.
Following the ambush, a reputed Taleban spokesman said Mr Addison had received treatment for a bullet wound to his hand, but was fine.
Mr Howells said the lorry driver's body was found by coalition forces who had been trying to trace and rescue him at Britain's request.
He expressed "deep condolences" to the dead man's family and friends on behalf of the UK government.
'Thugs and gangsters'
The Foreign Office minister said the Taleban killing had dealt a blow not only to Mr Addison's family but also to the future of Afghanistan, for which he had been working.
He added: "Like everyone else, I was living in hope that these people would see sense and realise that this is a man who was there to do good and not to harm them, or anyone else.
"But there's no rationale with these people. They simply want to kill. They want to make examples and that's what they do. They're twisted, they're thugs and they're gangsters."
Mr Addison was part of a team of engineers and road builders working on a major road between the southern city of Kandahar and the western city of Herat.
News of his death follows the discovery on Thursday of the bodies of two Japanese tourists who went missing in Afghanistan on 8 August.
They were thought to have been shot dead at least three weeks earlier, after having entered the country from neighbouring Pakistan, apparently to go sightseeing.
Insurgents have stepped up attacks in Afghanistan in the run-up to elections on 18 September.
More than 1,100 people have been killed in the last six months.