Back ramrod straight, heels together, hands behind his back, this is the moment General Sir David Richards became the first British commander since the Second World War to lead a multi-national force including the Americans in battle.

Wearing desert fatigues, cap badge pulled down over his left eye, a frown etched on his face, General Richards, second from the right, had just taken control of the Herat Room, the command centre at the heart of Nato's headquarters in Afghanistan.

Most unusually, this historic scene inside the military's main briefing room in Kabul was captured by a painter - British portrait artist Brendan Kelly, who spent more than a year and a half completing the work, which fills a huge 11ft by 5ft canvas.

Last night Mr Kelly said: 'I was commissioned as a war artist to go out to Kabul to paint a large group portrait of all the senior figures running the war in Afghanistan.

'I was always aware of artists who had done war paintings but never thought that one day I might head out to a war zone to do the same.

'It is rare today for a portrait painter to be asked to capture a moment in history. I guess that's normally left to other mediums, like film and TV.