A British soldier shot dead by a rogue member of the Afghan National Army has been named by the Ministry of Defence as 23-year-old Sapper Richard Walker.
The father-of-one, from Leeds, was serving with 28 Engineer Regiment, attached to 21 Engineer Regiment, on his first deployment to Afghanistan.
His family said he was a "proud, patriotic man... doing a job he loved".
Six British troops were also injured in Monday's incident as they undertook construction work in Helmand.
The soldiers were helping other military engineers at Patrol Base Hazrat, in the Nahr-e Saraj district, as part of preparations to transfer the camp to Afghan security forces.
Sapper Walker had worked as a technician for Vauxhall Motors before joining the Royal Engineers in July 2008 where he trained as a driver. He deployed to Afghanistan at the start of September last year.
His family said: "Richard held two things close to his heart - his daughter and his colleagues in the Army.
"A proud, patriotic man, he died doing a job he loved, supporting his friends".
Sapper Walker was said to be an an avid football fan who played for the regimental squad and had ambitions to take up boxing on his return from Afghanistan.
His commanding officer, Lt Col Chas Story, described him as the "epitome of a true sapper, one who would roll up his sleeves and get on with the task in hand no matter what, but importantly he would do it with great humour".
He added: "It is without doubt that he had a lot to offer and a bright future. This was his first tour of Afghanistan but anyone would have thought he was a seasoned expert, such was his ability and professionalism."
Tributes also came from Sapper Walker's friends in 28 Engineer Regiment.
Sapper Matthew Cunningham said: "He was thoughtful, funny and a big character in any group he found himself amongst, but he always put others first."
Secretary of State for Defence Philip Hammond MP said: "The tributes of his colleagues speak of a popular, committed soldier who was devoted to his unit and a dedicated family man.
"I send my deepest condolences to his family and loved ones at this sad time."
There has been a sharp rise in so-called insider attacks against local forces and Nato troops in Afghanistan. In 2012, more than 60 Nato service personnel, and a quarter of the British troops who died in Helmand, were killed in such attacks.
All six of the British troops killed during the latest six-month tour of duty have died this way. A total of 439 UK service members have lost their lives in Afghanistan since operations began there in October 2001.