By Sean Rayment, Defence Correspondent
Published: 8:30PM BST 03 Oct 2009
In an unprecedented intervention, the chief of the general staff described the conflict as "this generation's war" and added that failure by Nato would have an "intoxicating effect" on militant Islam.
In his first interview as the head of the Army, Sir David told The Sunday Telegraph that if Britain and Nato failed in Afghanistan the risks to the western world would be "enormous" and "unimaginable".
He said: "If al-Qaeda and the Taliban believe they have defeated us – what next? Would they stop at Afghanistan? Pakistan is clearly a tempting target not least because of the fact that it is a nuclear-weaponed state and that is a terrifying prospect. Even if only a few of those (nuclear) weapons fell into their hands, believe me they would use them. The recent airlines plot has reminded us that there are people out there who would happily blow all of us up."
The general's intervention comes at a crucial time, with the US General in charge of operations in Afghanistan calling for more troops to be sent to the country to fight the Taliban.
At home, the Government has come under increasing pressure for the way it has handled the war, with critics saying the armed forces have been under-resourced.
Yesterday The Daily Telegraph reported that the Prime Minister believes that he has been "let down" over the running of the Afghan War by Air Chief Marshal Sir Jock Stirrup, the chief of the defence staff. Suggestions that Sir Jock may be forced to step down, however, have been denied by senior defence sources.
The increasing tensions come against a background of rising British casualties.
Yesterday the Ministry of Defence named a 24-year-old member of the Royal Air Force Regiment who died in a blast near Camp Bastion in Helmand on Thursday. Aircraftman Marcin Wojtak is the 219th member of the armed forces to have died in Afghanistan since the conflict began in 2001.
Sir David has issued his unprecedented warning because he believed the public and even members of the government had not "woken up" to the "enormous risks" which would result if the war was lost.
He said: "Failure would have a catalytic effect on militant Islam around the world and in the region because the message would be that al-Qaeda and the Taliban have defeated the US and the British and Nato, the most powerful alliance in the world. So why wouldn't that have an intoxicating effect on militants everywhere? The geo-strategic implications would be immense."
Sir David, who succeeded Gen Sir Richard Dannatt as head of the Army, said that a failure by the public to back the war would ultimately "delete" troop morale – an effect which, he said, would be far more damaging than a lack of resources.
The Army chief declared that Britain was ready to send more troops to Afghanistan if called on to do so in the wake of the revised strategy which has been drawn up by Gen Stanley McChrystal, the US commander of Nato troops in southern Afghanistan.
He said that more troops would result in fewer casualties and would allow British and Nato troops to deliver greater security more quickly.
Sir David also warned that the "drumbeat" of casualties in Helmand would continue for another three to five years, while the war raged on, but added that the Army was ready to bear the sacrifice.
Sir David said that sending extra troops would allow Nato to begin winning the psychological battle against the Taliban who, he said, were masters of propaganda and were "outstanding at psychological warfare".
He continued: "If you put in more troops we can achieve the objectives laid upon us more quickly and with less casualties. We can start winning the psychological battle which is broadly wrapped around the Taliban saying "the west and the Afghan government is doing very little for you" – we (the Taliban) will offer you an austere future but at least it will be secure". What we need to demonstrate is that we, Nato and the Afghan government, offer a much brighter future which is more secure, with jobs, and education and better health."
In a wide-ranging interview, Sir David denied that success in Afghanistan amounted to "mission impossible" but admitted that it was "certainly difficult", adding: "Having spent the last five years more focused on Afghanistan than anything else, I'm convinced it is most certainly doable. We all know if we get this wrong there are all sort of implications not just for this generation but for our children's generation."
The general criticised plans put forward by some members of President Obama's administration – notably those of Vice-president Joe Biden, who is believed to support the view that Nato should reduce troop number in Afghanistan and concentrate on counter-terrorist operations using special forces. Sir David said this was a strategy which would not work.
The general's comments follow those of Gen McChrystal, who last week said that the campaign had been under-resourced in the past to meet the objectives set by the international community. He added that the coalition of 42 nations serving in Afghanistan had "underperformed" in some areas.
He said: "The situation is serious and I choose that word very, very carefully. Neither success nor failure in our endeavour in support of the Afghan people and government can be taken for granted."
On other military matters Sir David said that he would like better pay for soldiers and added that he believed that the review of compensation for wounded soldiers would lead to "improvements" in future payouts.