British extremists should be allowed to join ISIS in Syria because if they are killed it would boost the security of the UK.

This is according to Labour MP Frank Field, a committed Christian, who said he was not worried "one iota" about the prospect of jihadis leaving to fight in Syria.

Field said: "I think we should have no worries about letting them go because the chances are some of them will get killed and that increases the security of this country.

"If people want to practise their evil, better go and practise it with the mates who've actually taught them about this evil than inflict it on my constituents or anybody else."

Field, a former government minister and chair of the work and pensions select committee, told BBC Radio he was not talking about the case of Kadiza Sultana, the 17-year-old who ran away to join ISIS last year. He said her case was "horrendous" and the government had a duty to protect children. But he said it was different with adults.

"If adults want to go over there and get killed, fine," he said, adding it would be crucial to know if any returned to the UK.

The Birkenhead MP later defended his remarks and said: "I am relaxed about letting them go but I am unbelievably tough about letting them back in again.

"The resources used to control their going should be used to prevent them coming back."

Field's comments were branded "irresponsible" by Tory MP Alec Shelbrooke.

"Not only is this irresponsible, it's ill-thought-out," he said.

"It's not looking at the long-term consequences – even if British jihadis in Syria don't come back here to carry out terrorism acts, they can act as a recruiter of more people from this country to go out there."