UK ‘rebuffed my 
offer to help free Henning’

Mr Begg said he believed he knew those who held the murdered aid worker and had helped secure the release of hostages from extremists in Syria in the past.

Mr Henning’s brother Reg urged Mr Begg to make similar efforts to save the lives of other hostages held by IS, including British photojournalist John Cantlie and US aid worker Peter Kassig.

A video showing the brutal murder of Mr Henning, who was kidnapped in Syria by IS militants last December, was posted on the internet by the group last week.

Reg Henning told the BBC: “If Moazzam Begg believes he could have saved my brother’s life I would ask him to make the same efforts to save the lives of all hostages in Syria including John Cantlie and Peter Kassig.”

Former Middle East Minister Alistair Burt confirmed that he had met Mr Begg and said he was confident the Foreign Office (FCO) had handled the issue appropriately.

The FCO’s policy is to speak to anyone it believes may be able to help kidnap victims, and all offers of assistance are usually considered by experts in hostage situations.

Mr Begg claimed his offer was initially rebuffed by the FCO and he was subsequently told he could deliver a message to IS, also known as Isis or Isil, through an intermediary of the Government’s choosing but not directly.

He told BBC Radio 4’s Today programme the message could not have been delivered by anyone else because of the connection he could have made with the militants.

Mr Begg said he had been asked by friends of Mr Henning in December 2013 if he could help secure the 47-year-old’s release.

He then approached Mr Burt to explain that he was going to make contact with people connected to IS to see if he could secure Mr Henning’s freedom.

But Mr Begg’s help was turned down and weeks later he was arrested.

From prison he said he approached the FCO again through his lawyer to make clear that he thought Mr Henning was still alive and to ask if he could deliver a video message to IS leader Abu Bakr al-Baghdadi.

Mr Begg said: “Abu Bakr al-Baghdadi himself had been a prisoner of the Americans so it was a very heartfelt, very direct statement that I wanted to make in the Arabic language.”

Mr Begg, who was released from prison last week after terror charges linked to the civil war in Syria were dropped, also said he believed he knew those responsible for Mr Henning’s detention.

A FCO spokesman said: “We have a long standing policy of not commenting on the operational detail of our handling of kidnap cases. The safety of British nationals is paramount.”

Meanwhile, David Cameron faced fresh pressure to extend the RAF’s air campaign against IS into Syria as the extremists maintained their assault on a town close to the border with Turkey.

Air strikes by the US-led coalition have so far failed to halt the attack on Kobani in Syria,.

Former Foreign Office minister Alistair Burt said it was “probably correct” that the only way to halt the advance of IS was for Britain to join in action against the extremists in Syria.

Turkey’s president Recep Tayyip Erdogan warned that Kobani is about to fall to IS, and called for “co-operation with those who are fighting on the ground”.