The two latest casualties were killed by a roadside explosion despite traveling in a Jackal, a fortified patrol vehicle which was sent to Afghanistan to beef up protection for troops following criticism of the use of lightly-armoured Land Rovers. The Jackal was described by the Army as having "as much power as a tank" when it was introduced over the summer and the MoD last month agreed to buy 100 more for use in Afghanistan, reported The Independent.
Critics of Snatch Land Rovers, in which 36 officers have so far died, concede the Jackal offers more defence, but warn the risk of booby traps could be more significantly reduced with more movement by air.
Conservative MP Patrick Mercer, a former infantry officer, said: "If we want to save lives we need to get the troops out of these vehicles and put them in helicopters. They are vulnerable but not as vulnerable as road vehicles. There's a shortage of helicopters in Afghanistan."
The MoD said that it was investigating the circumstances of the latest blast in the Garmsir District of southern Helmand. A third marine survived the blast but was severely injured, it confirmed.
Defence Secretary John Hutton said: "The work they were doing was important for the national security of the UK as well as for Afghanistan, but we remember the individual cost of that work."