The kidnappers' cruel message: If Bigley dies, it will be Blair's fault

For a week they had endured the silence of the kidnappers. As the pall of dread hung over them, the Bigley family watched as other captives walked free and wondered if, just maybe, those holding Ken might be beginning to bend.

Early yesterday, an e-mail purporting to be from the hostage-takers offered freedom. But just after 2pm, Abu Musab al-Zarqawi's Tawhid and Jihad group dashed those hopes - at least for now - releasing instead fresh video footage of the 62-year-old civil engineer.

With his hands and legs chained, briefly cradling his head in one palm as he pleaded between tears for his life, Kenneth Bigley's appearance was carefully tailored to underline the cruel power of his captors.

Manacled about the neck and crouched in a wire cage to mimic the conditions of detainees in Guantanamo Bay, the civil engineer condemned Tony Blair as a liar and begged him to meet his captors' demand to release female prisoners held by American forces in Iraq. Then, with careful precision, the kidnappers offered one tantalising glimmer. With their black and yellow sunburst banner pinned behind him, Mr Bigley said: "My captors don't want to kill me."

The message from Tawhid and Jihad was perverse but clear: we do not listen to pleas. No release is imminent. If this man is to die, it is the fault of the British Prime Minister.

Within minutes of the release of the video of Mr Bigley on the Arabic television channel al-Jazeera, the images were being flashed across the world by 24-hour news stations and the fate of Mr Bigley was instantly returned to the top of the political agenda.

Zarqawi, the Jordanian-born Palestinian who leads Tawhid and Jihad (Unification and Holy War), had once more shown his perverse talent for combining barbarity with showcasing his cause to an international, prime-time audience.

Paul Bigley, the brother of the hostage, said that the images had been "heart-breaking" but still offered grounds for hope. Speaking from his home near Amsterdam, he said: "It is appalling. For a week we have heard nothing and now we see this. They [the kidnappers] are saying something needs to be done quickly. They have made these demands and they want Mr Blair to give way, whatever those demands are.

"We know Ken's alive. It is horrible to see him in the conditions they have him. This is designed to have the maximum impact. Something does need to be done. And it does need to be done very quickly." The tone of restrained anguish among family members was reflected further by Mr Bigley's son, Craig, 33. In a carefully worded statement directed at the kidnappers, he thanked them for the latest message but urged them to show mercy.

"We want to thank you for this opportunity to see him alive again," he said. "His continued captivity is putting great strain on his mother, Lil, my grandmother. From her hospital bed, she has asked us to pass on her love to her son. My dad, Ken Bigley, is an elderly man who is only a few weeks from retirement - and from becoming a grandfather ... We once again ask you, please show mercy to my father and release him."

Mr Bigley's older brother Stan, 67, a retired lorry driver from Wigan, added his voice to the continued chorus of family appeals. Referring to the most recent video, he said: "It gives me hope, it gives us all hope that he is still alive. We are all glad. We just hope to see him safely home. Apart from that, there is nothing else to say - I am just waiting for that call."

Yesterday's scratchy recording was released eight days after the kidnappers completed the beheading of the two Americans abducted with Mr Bigley from their house in the wealthy Mansour district of Baghdad. The intervening period - punctuated by the Briton's first recorded plea to save him and an Iraqi initiative, halted by Washington and London, to release the female weapons scientist Dr Rihab Taha - was interpreted by relatives as evidence that the kidnappers werebeing influenced by events.

But the new videodashed hope in the home of the Bigley family in the Liverpool suburb of Walton just as it had begun to rise with the release on Tuesday evening of two Italian aid workers who had been held by a different group for three weeks.

Hours before the tape, delivered anonymously to the Baghdad office of al-Jazeera, a message on an Islamist website which has previously carried genuine messages from Tawhid and Jihad appeared to suggest Mr Bigley could be set free. The communiqué, claiming to be from intermediaries in communication with the kidnappers, stated that the Briton was being spared, if only to underline the "indifference" of his Government to his fate.

It read: "Let his liberation be a clear message to the British people and also an appeal for them to realise the incapacity of their government and its crime in not freeing Iraqi prisoners in exchange for the life of their son.

"To emphasise the humiliation of the British Government and its Army, Tawhid and Jihad has decided to spare Bigley ... giving him his life and sparing him the punishment he deserved for helping criminals who have killed Iraqis in numbers that cannot be counted."

The Foreign Office said it was trying to establish the credibility of the statement and a number of similar communiqués. Despite claims from Mr Bigley that he was "100 per cent certain" the kidnappers had approved the statement, sources said it was possible it was instead a formula being suggested to Tawhid and Jihad by intermediaries in the event that they release the Briton.

Experts said the video and its imagery mimicking American treatment of suspected terrorists represented an increasingly sophisticated use by Tawhid and Jihad - and in particular Zarqawi - of publicity.

It is unlikely Tawhid and Jihad is timing its videos to respond to events such as Mr Blair's speech to the Labour Party conference. But there seems little doubt that the group is seeking to make the Prime Minister pay a political price for the hostage crisis.

Dr Toby Dodge, an Iraq expert at Queen Mary University of London, said: "Zarqawi is playing to an international audience to say two things. First, he wants his group to the rallying point for trans-national Jihadists. Second, he now knows he can generate huge international media interest to underline the impotence of Mr Blair. The danger will come when Zarqawi thinks he is no longer getting that publicity."