The Prime Minister admitted the UK has "paid a very high price for the work we are doing in Afghanistan" after three British soldiers were killed in a roadside bomb attack.
The deaths take the number of UK service members who have lost their lives since operations in Afghanistan began in October 2001 to 444.
David Cameron told ITV's Daybreak: "We have paid a very high price for the work we are doing in Afghanistan.
"It is important work because it is vital that that country doesn't again become a haven for terrorists, terrorists that can threaten us here in the UK but today our thoughts should be with the families and friends of those that have suffered."
Family, friends and colleagues have been remembering three British soldiers killed in a roadside bomb in Afghanistan.
The deaths of three British soldiers in one incident in Afghanistan still has the power to shock us. And yet it is no surprise.