LONDON suicide bomber Mohammad Sidique Khan blamed the British public for the July 7 atrocity in a chilling terrorist video and warned: "We are at war".

The mass killer, who lived a seemingly normal life in Thornhill Lees, was shown in a film broadcast last night by Arab television channel al Jazeera.

And in the terrifying film, al Qaida made a direct claim to have been behind the bombings.

The video, recorded as a final message before Khan's suicide attack, saw the father-of-one teaching assistant tell the public they would be targeted again in future.

Speaking in a slow, calm tone and with a distinct Yorkshire accent, Khan warned: "Until we feel security, you will be our target. Until you stop the bombing, gassing, imprisonment and torture of my people, we will not stop this fight.

"We are at war and I am a soldier. Now you too will taste the reality of this situation."

He added: "Our words are dead until we give them life with our blood."

Khan is thought to have been the ringleader of the four-strong suicide bomber gang who brought death to London on July 7.

The others included 18-year-old Jermaine Lindsay, who was brought up in Rawthorpe and went on to kill 26 people on a Tube train near Kings Cross.

Khan said on the tape he was inspired by al Qaida leader Osama bin Laden and the reputed leader of al Qaida in Iraq, Abu-Musab al Zarqawi.

Suspected to be the ringleader of the July 7 gang, Khan was shown wearing a red-and-white checked "keffiyeh" and a dark green, hooded jacket.

He appeared with a trimmed beard and was sitting against a wall lined with a striped red and beige carpet.

The suicide bomber, who killed six people on a Circle Line train at Edgware Road, can be seen fiddling with a pen and glancing at notes.

Khan, 30, who lived in Lees Holm, a quiet street in Thornhill Lees, claimed bombings in London and in Madrid in 2004 were the fault of Western citizens.

"Your democratically elected governments continuously perpetuate atrocities against my people and your support of them makes you directly responsible, just as I am directly responsible for protecting and avenging my Muslim brothers and sisters," he says in the tape.

The video, screened for the first time last night, also featured Ayman al Zawahri - said to be al Qaida's second in command - and he confirmed the terror group was behind the attacks in the capital which claimed 52 innocent lives.

On the tape al Zawahri repeated his claim Tony Blair's decision to go to war in Iraq was responsible for the outrage and warned of "more catastrophes".

The Egyptian was not seen together with Khan and it was not known if the men were in the same location or filmed at the same time.

A security expert has claimed that a delay in the release of the video may be part of a propaganda war over Iraq.

Former US intelligence officer Bob Ayers, now based in London, said the film may be part of an attempt by the terror network's leading figures to use the atrocity for their own ends.

"There are two possible explanations about the delay in releasing this footage, the first is that it may be simply the difficulty of passing it hand to hand before it reaching a TV station," he said. "Another possibility is that al Qaida may have been trying to look for a way for their leaders to retrospectively claim some credit for this attack."

Scotland Yard said it was aware of the existence of the tape. A spokeswoman said: "We are aware of the tape and it will form part of our ongoing investigation."

Downing Street declined to comment of the film.

Dressed in a black turban and white robes with an automatic weapon leaning against a wall behind him, Zawahri said: "Blair not only disregards the millions of people in Iraq and Afghanistan, but he does not care about you as he sends you to the inferno in Iraq and exposes you to death in your land because of his Crusader war against Islam."

Chilling words of suicide bomber:

I am going to keep this short and to the point because it's all been said before by far more eloquent people than me.

"But our words have no impact upon you therefore I'm going to talk to you in a language that you understand. Our words are dead until we give them life with our blood.

"I'm sure by now the media has painted a suitable picture of me, this predictable propaganda machine will naturally try to put a spin on it to suit the Government and to scare the masses into conforming to their power and wealth-obsessed agendas.

"I and thousands like me are forsaking everything for what we believe. Our driving motivation doesn't come from tangible commodities that this world has to offer.

"Our religion is Islam, obedience to the one true God, Allah and follow in the footsteps of the final prophet and messenger Mohammed.

"This is how our ethical stances are dictated. Your democratically elected governments continuously perpetuate atrocities against my people and your support of them makes you directly responsible, just as I am directly responsible for protecting and avenging my Muslim brothers and sisters.

"Until we feel security, you will be our target.

"Until you stop the bombing, gassing, imprisonment and torture of my people, we will not stop this fight.

"We are at war and I am a soldier.

"Now you too will taste the reality of this situation."