As shipping containers start to replace the tents and tarpaulin at the New Jungle migrant camp in Calais a former counter-terrorism chief from Britain said Isis fighters may be hiding among the refugees.

During a visit to the camp for a BBC documentary Kevin Hurley a former head of police counter-terrorism said the camp may be a refuge for returning jihadis to “hide in plain sight” before “smuggling themselves” into the UK.

Hurley was told by migrants that there were “dangerous people” operating inside the camp and one Iraqi-Kurd told him: “Of course Islamic State jihadis were in the camp”.

Speaking after the documentary for BBC’s Inside Out programme Hurley added: “I was told people from Islamic State were definitely in there.

“The fact is, we have absolutely no idea who is there because it’s completely unpoliced. It is precisely the sort of place I would hide if I was a jihadist – in plain sight.”

“I’m very concerned about the possibility of criminals and terrorists hiding here as they wait for their chance to slip into Britain,” said Hurley who is currently Surrey police’s crime commissioner.

“These people are extremely determined. They are not going to give up.”

Fears that jihadists would hide among refugees to sneak into Europe were heightened after it emerged two of the Paris attackers had travelled through Greece posing as refugees.

The British government has long been concerned the same tactic may be used by would-be terrorists to get into the UK.

However those who have spent far more time in the New Jungle than Hurley have dismissed the ex-policeman’s claim as “stupid” and “scaremongering”.

“These people are the ones fleeing war, so it’s a totally stupid thing to say,” Vincent de Coninck from the charity Secours Catholiques told The Local.

“It’s not intelligent to say things like this, because it only stigmatizes the refugees who are there, who are in need of aid.”

Clare Moseley who founded the charity Care4Calais told The Local: “The overwhelming experience of both myself and the Care4Calais team is that all the individuals we meet in the camp are just ordinary people who have experienced terrible things and desperately need our help, support and compassion.

“The people here in the camp fear ISIS and the like as much, if not more, than we do. ISIS is the reality they flee from.”

Jean Francois Corty, who heads up the Medecins du Monde operation in Calais told The Local he had no idea of the presence of jihadis in the camp but the question should not hide the real humanitarian disaster that is taking place.

“It's not because there might be a jihadist in the camp that people should be left to sleep outside with no food and water,” he said.

“There's people in real danger here.”

(New containters replace thetents atthe so-call 'Humanitarian Camp'. Photo: AFP)

The row comes as the Jungle in Calais takes on a different form with Monday seeing the new sheltered accommodation for refugees open to a number of families.

Shipping containers have been converted into sheltered accommodation for the refugees which will replace some of the tattered tents and tarpaulins that have only provided minimal cover for the refugees.

There are fears that the new semi-permanent structure will end up like the infamous Sangatte detention centre, which had to be closed in 2002, after being overrun by criminal gangs.

The new camp, being built alongside the Jungle has been named “the humanitarian camp” by French authorities, who have been under pressure to improve conditions for migrants living in the squalid shanty town.

Eventually around 1,500 people will be offered shelter in the containers.

But aid groups say it’s not enough, considering there are between 4,000 and 6,000 refugees and migrants in Calais.

So we are unlikely to see the end of the sprawling mass of tents anytime soon.