Thomas Mair, 52, has been charged with the murder of Labour MP Jo Cox

A hard-right group connected to Thomas Mair (pictured) is linked to the Brexit campaign, The Mail on Sunday can reveal

A hard-right group connected to Thomas Mair is linked to the Brexit campaign, The Mail on Sunday can reveal.

Our investigation has established that the racist Springbok Club, which once described Mair as one of its ‘earliest subscribers and supporters’, has sent newsletters to British members urging them to support the Leave campaign.

The leaflets, all sent in the last three months, say:

Supporters should ‘suspend all activities’ to focus on securing a Leave vote in the referendum;

Subscribers should sign a referendum petition which criticises David Cameron;

Britain has been ‘invaded by millions of ethnically alien migrants’ who it blames for a big rise in ‘lawlessness’.

The Springbok Club is part of the Patriotic Forum, which moved from South Africa to Britain after the downfall of apartheid.

Its newsletter in April said that the anti-EU Bruges Group had ‘asked for help’ with a Vote Leave campaign centre it had set up in West London.

And it congratulated the ‘Swinton Circle’ – a sister far-Right British outfit under the Patriotic Forum umbrella – for ‘deciding to suspend all activities so that supporters can concentrate solely upon campaigning for a Vote Leave victory’.

March’s newsletter promotes an anti-EU petition, initiated by ‘our friends in the Get Britain Out campaign’ entitled ‘Stop Cameron spending taxpayers’ money on Pro-EU Referendum leaflets’.

The June newsletter said the EU was ‘always intended to be a political project, whereby the belligerent aggressors from the two World Wars of the 20th Century [Germany] could achieve their goal of domination of the European continent by “peaceful” means after they had failed to achieve the same aim by armed invasions’. It added that the UK had been ‘invaded by millions of ethnically and culturally alien migrants threatening [its] national identity,’ and crime had ‘risen out of all proportion as a direct result of their lawlessness… It is almost impossible to understand why any British voter would want to remain in the EU.’

Popular MP Jo Cox died after she was shot three times and stabbed as she arrived for a constituency meeting in Birstall near Leeds

Thomas Mair appeared in the dock at Westminster Magistrates Court, where he was charged with the murder of Jo Cox

The banner of the racist Springbok Club, which once described Mair as one of its ‘earliest subscribers and supporters’

May’s newsletter promoted support for apartheid and included a reader’s letter which said South Africa is now ‘governed by savages’. It claimed Sadiq Khan’s victory as Mayor of London had ‘brought shame and humiliation on the British nation’, asking: ‘How come the White electorate of London voted for not only a non-White, but even worse a non-White Muslim? The USA went mad and elected a Coloured President… now the people of London have gone mad.’

Tories and Labour now both had ‘a dozen racial aliens as MPs’, the group claimed. Another far-right group linked to Springbok is the German-based Pegida, notorious for its demonstrations against Islam and immigration.

The April newsletter said its British offshoot, Pegida UK, had ‘specifically contacted’ the Swinton Circle as a ‘similarly-minded organisation’ and asked them to ‘support their forthcoming activities and campaigns’.

Last night the Bruges Group denied any contact with the Springbok Club or the Swinton Circle.

The Springbok Club said: ‘We were appalled and sickened to learn of Jo Cox’s murder.’ It added that Mair had no contact with the organisation since the 1980s.

‘We have never met Mr Mair and all attempts to try to link our magazine with him during more recent years are without foundation.

‘Mr Mair has never been a subscriber to the Springbok Cyber Newsletter. It was the Swinton Circle which the Bruges Group asked for support in their Vote Leave campaign’.

A Vote Leave spokesman said it had no connection to the Springbok group and no knowledge of the Bruges Group’s alleged invitation.