Why wasn’t he kept under surveillance?

THERESA May was under growing pressure last night to explain how a known extremist was able to flee Britain and blow himself up on the Islamic State front line.

The prime minister faced calls to lay bare what she knew about the risk former Guantanamo Bay inmate Ronald Fiddler posed to the British public.

Her spokesman was forced onto the defensive as he refused 18 times to say how the 50-year-old was able to leave the country despite his extraordinary background.

Critics called on Mrs May, who was home secretary when Fiddler travelled to Syria three years ago, to reveal what assurances she was given by the security services. Fiddler was arrested in lawless southern Afghanistan and held at Guantanamo for two years as US authorities warned he was linked to Al Qaida.

They said that his back story as a backpacking Islamic scholar simply did not add up, and that he may even have spent time with Osama bin Laden in Sudan.

But there are fears Fiddler and other committed Islamists simply drop off the radar after being released from custody, pocketing huge pay-offs.

His family claim he was not even fully debriefed by the security services after he told them he had already spent two years ‘answering questions’.

But David Blunkett, who was home secretary when Fiddler and others were released from the US prison camp, insisted police and security services reassured him that no-one allowed to return would pose a risk to the British public.

In a fearsome broadside, he questioned whether the same measures continued after the Coalition Government came to power in 2010. The former Labour MP highlighted that it was the Conservative-led government that signed off the secret bumper compensation pay-outs.

But Northern Ireland Secretary James Brokenshire, who worked alongside Mrs May in the Home Office, insisted the security services are doing an ‘incredible job’.

‘There is ongoing monitoring that is undertaken by security and intelligence agencies. We are investing more heavily into their work,’ he told the BBC.

‘The security and intelligence agencies do an incredible job and we have given them extra powers to be able to disrupt.’