Deputy Prime Minister Nick Clegg also paid tribute, saying: "Our thoughts are with the families and friends of the five service personnel who have so tragically lost their lives.
"This incident is a very sad reminder of the vital but dangerous job that our Armed Forces are doing every day to bring security to the people of Afghanistan.
"I would like to pay tribute to their service and to the ultimate sacrifice made by those who died yesterday."
More top news
No one gave him a chance - but Donald Trump has just pulled off one of the greatest feats in modern American political history.
German police are investigating an online picture thought to be of two British men doing a Nazi salute at a former concentration camp.
Late sunshine here and there this evening - but more cloud for southern Scotland, northern England and Northern Ireland again.