The man arrested over the killing of Labour MP Jo Cox is believed to have had long-term links with a hard-right group based in London which had been campaigning for many years for Britain to leave the European Union.

Thomas Mair was named as a supporter in an online publication of the Springbok Club, an organisation which has defended the white supremacist apartheid regime in South Africa.

Witnesses to the fatal attack on Ms Cox say they heard Mair shout “Britain First” as the MP was shot and then stabbed. The organisation Britain First, which was founded by former members of the British National Party, has denied that Mair was associated with it and say they condemn the killing.

The link between Mair and the Springbok Club goes back ten years when its online magazine, the Springbok Cyber Newsletter, was inquiring about the whereabouts of “Thomas Mair, from Batley in Yorkshire [who] was one of the earliest subscribers and supporters of “S.A. Patriot” who has moved from his address in the Fieldhead Estate district of the town.”

Cox murder suspect arrest

The leading article for June 2016 Springbok Cyber Newsletter, which describes itself on its website as being pro-free market capitalism and patriotism and anti-political correctness, was, however, devoted to Britain and the referendum. It started: “On Thursday, 23rd June 2016 all British voters will have the opportunity to vote on the future of their country. They can vote either to remain entrapped in the artificial and retrograde European Union, or to regain their sovereign independence....”

The article ends by declaring: “But we should not only be concentrating at the negative aspects of remaining in the EU. Our campaign should be primarily positive and optimistic for a future outside the EU. The motto of the Patriotic Forum (an umbrella grouping of patriotic organisations which the Springbok Club is part of) is “Out of Europe and into the World”. There is a golden future waiting for Britain out there once the country returns to its traditional vision of looking towards the Open Seas and its ethnic brothers and sisters in the Commonwealth around the globe. The days ahead will inspire us!”

It is not known if Mair had renewed his connection with the Springbok Cyber Newsletter.

In May 2010 Mair was himself in the news. In an interview with the Huddersfield Daily Examiner he talked about getting work at a local park after being referred to a clinic for adults with mental health problems.

Jo Cox tributes - in pictures Show all 20 1 /20 Jo Cox tributes - in pictures Jo Cox tributes - in pictures Floral tributes and candles are placed by a picture of slain Labour MP Jo Cox at a vigil in Parliament square in London AFP Jo Cox tributes - in pictures Tributes to Labour Party MP Jo Cox are placed on her houseboat in Wapping in London REUTERS Jo Cox tributes - in pictures The Union flag at half-mast on top of Portcullis House in London after Labour MP Jo Cox was shot and stabbed to death PA Jo Cox tributes - in pictures Labour leader Jeremy Corbyn (2R) and deputy leader Tom Watson (L) light candles as they attend a vigil to slain Labour MP Jo Cox in Parliament square in London AFP/Getty Images Jo Cox tributes - in pictures Labour Party leader Jeremy Corbyn and deputy leader Tom Watson (rear) arrive to leave tributes at Parliament Square PA Jo Cox tributes - in pictures People leave St Peter's Church after a vigil in memory of Jo Cox REUTERS Jo Cox tributes - in pictures Flowers left at Parliament Square opposite the Palace of Westminste, following the death of Labour MP Jo Cox PA Jo Cox tributes - in pictures People react as they look at tributes left for Labour Member of Parliament Jo Cox in Parliament Square, London REUTERS Jo Cox tributes - in pictures A man writes a message at Parliament Square PA Jo Cox tributes - in pictures People stop to look at tributes left at Parliament Square opposite the Palace of Westminster PA Jo Cox tributes - in pictures A woman arrives to lay flowers at a statue to Joseph Priestly in Birstall near to the scene where Labour MP Jo Cox was shot AFP/Getty Images Jo Cox tributes - in pictures Tributes at Parliament Square opposite the Palace of Westminster PA Jo Cox tributes - in pictures A woman places candles in tribute to Labour Party MP Jo Cox REUTERS Jo Cox tributes - in pictures A member of the public signs a memorial for British MP Jo Cox in Parliament Square, London EPA Jo Cox tributes - in pictures People sign messages of condolence for MP Jo Cox during a vigil in Parliament Square in London Getty Images Jo Cox tributes - in pictures Flags at half mast outside Scottish Parliament in Edinburgh, after Labour MP Jo Cox was shot and stabbed to death in the street outside her constituency advice surgery in Birstall PA Jo Cox tributes - in pictures People arrive in Market Square with floral tributes after the death of Jo Co Getty Images Jo Cox tributes - in pictures Floral tributes are placed in Market Square next to the statue of Joseph Priestley following the death of Jo Cox Getty Images Jo Cox tributes - in pictures Floral tributes are brought to the scene after the death of Jo Cox Getty Images Jo Cox tributes - in pictures A police officer carries bunches of flowers at the scene of the shooting of Labour MP Jo Cox in Birstall REUTERS

He said: “I can honestly say it has done me more good than all the psychotherapy and medication in the world. Many people who suffer from mental illness are socially isolated and disconnected from society, feelings of worthlessness are also common mainly caused by long-term unemployment.All these problems are alleviated by doing voluntary work. Getting out of the house and meeting new people is a good thing, but more important in my view is doing physically demanding and useful labour.”

Neighbours described how he would do gardening chores for local people.

David Pickles said: “He's lived there longer than me and I've lived here since 1975. I still can't believe it. He's the last guy I would have thought of.

”He's just quiet. He kept himself to himself. He lived by himself. He's been on his own for about 20 years.

Another neighbour, who did not want to be named, said: “We've known him quite a lot of years. I've known him since I was young. He lived with his grandmother in that house, she died a few years ago. He was a bit of a loner. It's a bit of a shock - he did everyone's gardens.

”I can't say a wrong word about him, he was so quiet. It's come as a shock to everybody.“