Defence Secretary Bob Ainsworth flew into Afghanistan today as the death toll of British soldiers killed in the bloody conflict this year reached 100.

Mr Ainsworth pledged his support for UK forces and said his thoughts were with the family and friends of the latest British soldier to be killed.

He added that the mission in Afghanistan was vital to national security. “Here in Afghanistan there is a sense of very real progress in this mission and that we are putting things where they need to be,” he said.

Mr Ainsworth’s unannounced visit aimed to reinforce an appeal by the head of the British Army for the public not to judge the campaign in Afghanistan by casualties alone.

General Sir David Richards, the Chief of the General Staff, urged people to remain resolute, saying the latest death had increased his troops’ will to win.

He warned that more British soldiers would be killed in the months ahead, but insisted “we must steel ourselves for the cost” of continuing the Afghan mission.

Gen Richards said: “For those of us in the Army, whilst we grieve for a fallen comrade, his loss hardens our determination to succeed.

Battle

“The temptation to judge this essential campaign by casualties alone undervalues the tremendous efforts of our forces and our allies, and the progress they are making.”

The latest soldier to die, from the 1st Battalion The Royal Anglian Regiment, was shot dead yesterday in a gun battle with Taliban insurgents near the town of Nad-e Ali in central Helmand Province.

Prime Minister Gordon Brown said: “We will never forget those who have died fighting for our country and we must honour their memory.”

Conservative leader David Cameron said the death marked a “sad milestone”

Mr Cameron added that the loss was “a stark reminder of the daily threat our troops face”.

The bloody milestone came as the body of Acting Sergeant John Amer, 30, from Sunderland, was returned to British soil today – and the funeral service of 28-year-old bomb disposal expert Corporal Loren Marlton-Thomas, who was from Thornton-Cleveleys in Lancashire and lived in Braintree, Essex, took place.

This year has been the bloodiest for British forces since the Falklands War in 1982

The total number of UK troops who have been killed since the start of operations in Afghanistan in October 2001 is now 237.

By London reporter Sunita Patel