Gordon Brown paid tribute to four Royal Marines killed in Afghanistan on a visit to their comrades on the frontline today.

The Prime Minister’s surprise visit came the day after the soldiers died in the southern province of Helmand with three killed by a 13-year-old suicide bomber and the fourth in an unrelated attack.

He praised the soldier’s work in fighting a “chain of terror” stretching from the mountains of Afghanistan to the streets of Britain after flying into the frontline town of Musa Qala, which was recaptured from the Taliban last year.

Mr Brown again expressed his sympathy to the family and friends of those killed by the child bomber.

“It was a pretty cowardly act by the Taliban to use a 13-year-old child as a suicide bomber,” he said. “There is disgust and horror at these tactics being used.”

He said he had wanted to see for himself the “brilliant job” being done by the British forces to calm the situation and restore normality.

The Prime Minister said their work was vital not only to secure a safe future for Afghanistan, but for Britain too.

The next of kin of all the Marines killed yesterday have been informed and it is expected that the soldiers will be named today.

Reports suggest that, in the second incident, the 13-year-old approached the unit pushing a wheelbarrow in which a bomb was hidden under papers.

The teenager died as a result of the explosion. It is not yet known if he was a suicide bomber or if the bomb was detonated remotely.

Following talks with Afghan President Hamid Karzai in the capital, Kabul, Mr Brown announced that he had agreed the deployment of a British civilian task force to help tackle corruption and promote good governance in the central Asian state.

He said the UK’s 8,100-strong contingent of troops in Afghanistan was playing a vital role in keeping Britain safe.

“There is a chain of terror that comes from the Pakistani and Afghan mountains right to across Europe and can end up very easily on the streets of Britain,” said Mr Brown, standing alongside Mr Karzai at a Kabul press conference.

“British people are safer today because we have our troops working with the Afghan people to act against terror.”

The deaths of the four soldiers yesterday bring the total killed to date in Afghanistan to 132.

Mr Brown is due to fly on to India after his talks in Kabul.

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