Sergeant Matthew Telford knew why he was fighting in Afghanistan. In a letter to his four-year-old son, opened after his death on Tuesday, he said he was helping people there "live normal lives" because they had no one else to defend them.

But in his home town of Grimsby this week it was hard to find anyone else who supported the growing loss of life to protect the far-flung country. The town and neighbouring Clee-thorpes together lost two sons this week when a rogue Afghan policemen shot dead five of the servicemen training him, spurring concerns that al-Qaeda terrorists had infiltrated the police force.