UK ambassador Stephen Evans escaped injury after a military transport plane he was travelling in caught fire at an airstrip in southern Afghanistan.
Helmand is one of Afghanistan's toughest areas
A number of Britons on board the Hercules C-130 were injured - none seriously - when the plane burst into flames on landing, near Lashkar Gah.
It is not known if gunfire or a burst tyre were responsible. All 27 people on board were "safe", officials said.
The ambassador was due to visit reconstruction programmes in the area.
More than 3,000 UK troops are based in the southern Helmand province.
The British troops are formed around elements of the 16 Air Assault Brigade and some soldiers staying in the capital are part of a reconstruction team.
Defence Secretary Des Browne told BBC News he had little information about what happened, but had been assured that all 27 people on board the plane were safe.
"The most important thing is everybody is safe," he said.
"But this is a very dangerous environment and flying C-130s or other planes in and out of this airstrip is inherently a difficult and dangerous thing to do."
Sgt Chris Miller, in Afghanistan, told the AP news agency a tyre burst and the incident was not the result of enemy fire.
The BBC's Alastair Leithead, at the British base in Lashkar Gash - 2km away from the airstrip - said a huge plume of smoke was visible for about an hour after the crash.
He said a burst tyre was one theory being examined, as was enemy fire.
"Obviously there's been a lot of fighting in southern Afghanistan over the past few days," he said.
The plane was completely destroyed in the crash.