Image caption Kevin Hurley said it was not possible for refugees to be subjected to detailed checks

The so-called jungle camp in Calais may be a refuge for returning jihadis to "hide in plain sight" before "smuggling themselves" into the UK, a former head of police counter-terrorism has said.

During a visit to inspect the area Kevin Hurley said he was concerned the camp was "completely un-policed".

But the head of a charity working at the camp called his claim "ridiculous".

The camp, on the outskirts of Calais, has grown in recent months and is now home to thousands of migrants.

Image caption The camp has grown in the past few months and is now home to thousands of migrants.

Mr Hurley, the former lead on counter-terrorism at the City of London Police and current police and crime commissioner for Surrey, spent several hours in the camp with BBC London's Inside Out team.

He said he was worried the camp was "a potential hiding space" and that people there could be being exploited by organised criminals.

"If I were a returning jihadi, I would smuggle myself in amongst this group; you would easily get lost," he said.

Speaking to migrants at the camp, Mr Hurley was told that there were dangerous people staying in the "jungle".

Image caption Claire Moseley, the founder of charity that works in the camp, dismissed Kevin Hurley's claims as "ridiculous"

One migrant said there were people at the camp who were "working for way of Daesh", although they were not part of the jihadist group.

Daesh is an acronym of the initial letters of the so-called Islamic State (IS) group's previous name in Arabic - "al-Dawla al-Islamiya fil Iraq wa al-Sham".

Another migrant from Afghanistan also told the BBC team there had been a murder in the area on the previous night.

A former Scotland Yard counter-terrorist investigator told the Inside Out team he had similar worries about the "jungle".

David Videcette said the "biggest risk" from the camp was UK nationals "who are trying to avoid detection by police... are now attempting to re-enter the country claiming to be asylum seekers".

However, the founder of Care4Calais, a UK charity set up to help migrants staying in the camp, dismissed the claims as "the most ridiculous thing I have ever heard".

Clare Moseley said: "You would have to be the world's stupidest terrorist to try and enter Britain as a refugee, because when you come as a refugee you are subject to detailed background checks."

Home Secretary Theresa May has previously told MPs all refugees coming to Britain will be subject to rigorous security checks to make sure IS militants are not among them.

Nevertheless, Mr Hurley insisted that it was not possible to carry out such detailed checks.

"You can't check a person with no passport coming from a fractured country", he said.

You can watch Inside Out on BBC One at 7.30pm on Monday 11 January and on the iPlayer for seven days afterwards.