An Al Qaeda fanatic who trains fellow Europeans to fight in Afghanistan has given a stark warning to our troops - by posing with a 2ft-long beheading knife.

The bearded terrorist, identified as ‘Abu Askar the German’, belongs to one of Osama Bin Laden’s ‘foreign legions’ fighting alongside the Taliban.

In a new terror video posted online he vows to 'achieve a victory for Islam' using the huge blade, which is inscribed with an Arabic passage from the Quran.

In pictures designed to scare British and American soldiers is also seen sitting with an AK47 rifle.

Terrorism expert and author Chris Dobson told The Sun: ‘The bloodthirsty threat of Abu Askar the German and his giant cleaver is plain - anyone who opposes us will lose their heads.

‘Fanatical Islamic Jihadists have a record of beheading captives and boasting about it to cause fear among their enemies.

‘Abu Askar and his knife are undoubtedly part of the “war of the mind” the Jihadists are waging against the West.

‘But they also reflect a growing confidence, especially among home-grown terrorists, that the West is becoming vulnerable.’

A message with the video says Askar belongs to a terror group closely allied to al-Qaeda.

It is known to hide out in the lawless Pakistan border region and cross into Afghanistan to launch attacks against British and US forces.

Askar boasted that the terrorists have attracted recruits from all over Europe as well as from Russia and China.

Britain’s Army commander, General Sir David Richards, has sounded the alarm over any possibility of losing the war in Afghanistan to men like Askar.

He said: ‘Failure would have a catalytic effect on militant Islam because the message would be that al-Qaeda has defeated the most powerful alliance in the world.’