From his remote and exposed operating base, Marine Calvert, of Charlie Company, 40 Commando Royal Marines, fights only for survival and thinks not of victory but only of going home to his girlfriend and young daughter.
Many who have served in Afghanistan would agree with his bitter feelings about the nearly decade-long war on the dusty lanes and sun-baked fields of Sangin in Helmand Province.
The Marine, who is half way through his second tour of duty in the country, says his view is shared by many in his troop which is made up of men from across the regiment – all of whom have seen friends lose their lives.
Only two weeks after this interview, Marine Adam Brown, of Alpha Company, 40 Commando Royal Marines, died in an explosion while on foot patrol in the Sangin District of Helmand province on Sunday.