The British Army is having to fight in Afghanistan with a "serious shortage" of helicopters and soldiers, a former Cabinet minister warned today.

Tory former Defence Secretary Lord King of Bridgwater said the military was now involved in a "critical" offensive which would determine the outcome of the whole campaign in the country.

Lord King, who was at the Ministry of Defence in John Major's government during the first Gulf War, threw his weight behind calls for better equipment for British forces.

He said some of the kit used by soldiers was getting a "tremendous bashing" but the most serious problem was the lack of lift capability and the shortage of troops.

The peer claimed "serious political mistakes" had been made by the Government and the duty of ministers now was to make everything available that commanders asked for.

Lord King, also a former Northern Ireland Secretary, told BBC1's Andrew Marr Show: "Some of the equipment is getting a tremendous bashing out there ... but where there really is a shortage, a really critical shortage, is helicopters.

"The degree to which they (British troops) need to be on the roads, the degree to which they need the supply convoys, whether some could be done by helicopter, which is what we did in Northern Ireland.

"When the roads became too dangerous we switched to helicopters, there appears to be a serious shortage at the present time."

Lord King claimed US forces in Helmand province had "eight times as many helicopters for the number of troops they have out there" and said British forces were having to "borrow" US helicopters.

Asked if British troops were dying because of the shortage he said: "Each incident is different in these cases, but certainly there are serious worries and quite clearly, they are borrowing helicopters from the Americans.

"But what matters now is this is the crunch time.

"We are in this critical offensive at the present time which I think will determine the outcome of the Afghan situation and the whole Afghanistan campaign."

He added: "This is a critical time and they must have the resources to do the job."