The mother of a young British man dubbed "Jihadi Jack" says reports he is a terrorist are "absolutely ridiculous" and that he has travelled to Syria to help refugees.

Jack Letts, 20, left his home more than a year ago and has since travelled to the war-torn region.

Over the weekend, it was widely reported that Mr Letts had become the first white British male to join the jihadist group and that he had married a woman from Fallujah and may have had a child.

Now, friends and family have angrily rejected the claims and accused the "right-wing" press of reporting misinformation about him.

His mother, Sally, says that she spoke to her son on Sunday: "He is not a member of Isis, he is very probably not the first white convert that has gone out there. He does not have a son and is not known as Abu Mohammed," she told the Standard. “We spoke to him yesterday and he said he had never had a weapon in his life. He went out there for humanitarian purposes to help kids in Syrian refugee camps.

“It is not as if he is hiding - he tells us what he has for breakfast. All this is absolutely ridiculous, it is shocking.”

Jack Letts wearing a hood in a picture he posted to Facebook. (Facebook)

“Somehow he is supposed to be a global jihadi? It is absolutely ridiculous.”

She added that police had been investigating them for more than a year but had found no evidence he had done anything wrong.

Describing him as "kind, funny and gentle", John and Sally Letts said they felt "betrayed" by the media coverage of their son in the press.

"The things they have written about him are completely false", they told the Oxford Mail.

In photos posted to Facebook, Mr Letts can be seen posing with a single raised index finger in front of what has been said to be the Tabqa Dam in Syria, an area under Isis control.

An anonymous close family member told the Mirror: “There has been an avalanche of misinformation. We don’t want to comment on all of this, but what I will say is that 95 per cent of what has been published is incorrect, it is desperately wrong.”

“The only truth is that Jack is a Muslim and he is overseas. But everything else is made up and it is just getting worse.”

The source also said that the “right wing” press were most “interested in a snappy line like ‘Jihadi Jack’ and ‘Jihadi John’ that rolls off the tongue, but it is all wrong,” the Mirror.

Mr Letts comes from a secular middle class background; his mother is a books editor and his father is a farmer who once won appeared on the TV programme Countryfile.

Some former school friends from Oxford dubbed him 'Jihadi Jack' (Image taken from Facebook)

A friend told MailOnline: 'I feel like he has been exploited. No one wants to fight in Isis unless they've been brainwashed. It's really alarming how powerfully he has changed.”

“He was always an atheist, pretty liberal, typical middle-class kid. At school he was the class clown but didn't take it too far, he was still smart and got fair grades."

Thames Valley Police said to The Independent: We are unable to comment on any specific cases in relation to individuals. However would say that anyone who knows of someone who may be potentially vulnerable to being drawn into terrorist-related activity, including travelling abroad to conflict zones should contact local police for advice and support on 101.