THE Ministry of Defence is to review the use of its heavily armoured vehicles after three Scots soldiers were killed in Afghanistan by a roadside bomb.

Last night the soldiers were named as Corporal William Savage, from Irvine, Ayrshire, Fusilier Samuel Flint, from Blackpool, and American-born Private Robert Hetherington, who was raised in Scotland. Next of kin have been informed.

Cpl Savage and Fusilier Flint were from the Royal Highland Fusiliers, 2nd Battalion The Royal Regiment of Scotland. Pte Hetherington was from the 51st Highland, 7th Battalion, The Royal Regiment of Scotland.

Six other soldiers were injured in the blast, which occurred on Tuesday while they were patrolling the Nahr-e Saraj district of Helmand province.

It was the first time troops had been killed while travelling in a Mastiff. At 24 tonnes it is deemed the safest vehicle in the British Army, with armour side-plating and a V-shaped hull for blast protection.

Lord Dannatt, the former Army chief, said the Taliban had found a way of countering the Mastiff's protective armour and added from what he had been told it was "in all probability a very large device in terms of the amount of explosive and it may well have physically lifted up the vehicle and possibly even turned it over".

David Cameron paid tribute to the fallen and said the country had paid a very high price for the work it was doing in Afghanistan. But he stressed the role of the armed forces was vital to prevent the country again becoming a haven for terrorists.

On troop safety, the Prime Minister said: "We have done an enormous amount to improve the quality and quantity of protective vehicles that our soldiers use in Afghanistan and this particular vehicle, as I understand it, had a pretty good record of withstanding blasts from IEDs [improvised explosive devices].

"I'm sure we want to look at that carefully and put in place everything we can to make sure our brave men and women have the best protective equipment."

Alex Salmond expressed his condolences to the families and loved ones of those killed and injured.

The First Minister said: "This incident demonstrates once again the dangers faced by our armed forces, often on a daily basis. They deserve our deepest gratitude and respect for the job they do in some of the most difficult and trying circumstances imaginable."

The three deaths take to 444 the number of UK service personnel who have lost their lives since operations in Afghanistan began in October 2001. Six have now died this year. The 350 soldiers from the Scottish regiment have been deployed in Afghanistan for only a matter of weeks.

They left their base at Glencorse Barracks in Penicuik, Midlothian, in March, to start a six-month tour of duty in the strife-torn country.

The battalion has taken over a number of roles, including mentoring and training Afghan National Security Forces to help prepare them for when Nato troops pull out next year.

The MoD said security in Helmand had been improving recently, with Afghan forces now responsible for most of the province, yet the environment in which British troops operated remained "risky and dangerous".

The latest attack came on the third day of what the Taliban dubbed its spring offensive.

There were other blasts throughout the country, which killed nine civilians and a police commander.

In past years, spring has marked a significant upsurge in fighting between the Taliban and Nato forces with their local allies.

The insurgents have warned they intend to infiltrate allied ranks to conduct "insider attacks" and target military and diplomatic sites with suicide bombers.

The number of British troops in Afghanistan was reduced to 9000 before the end of 2012 and is set to fall to 5200 by the end of 2013.