The English Democrats are to contest the by-election for the seat left vacant following the death of Jo Cox.
Therese Hirst, the party’s deputy chairman, and former leader of Veritas, will fight for the Batley & Spen seat.
The seat is also being contested by Liberty GB, which announced on its official website last month that Jack Buckby, a former BNP politician, will be its candidate.
The Conservatives, Liberal Democrats, UKIP and the Green Party have all said they will not challenge Labour in the by-election as a mark of respect after Mrs Cox was killed last month.
But the English Democrats said it is “only right that voters should have a choice”.
A spokesman said: “We felt is was right to wait until after Jo Cox’s funeral, before making the announcement.
“We wanted to be respectful, but we think it is only right that voters should have a choice, and as far as we are concerned this is a democracy and we felt we ought to stand.
“This is about what the people of Batley and Spen want to vote for. We will be giving them a pro leave (Europe) candidate whereas we think Labour will put forward a remain candidate.”
Therese Hirst stood in the Police Crime Commissioner Elections for West Yorkshire in May.
A retired RE teacher and part-time lecturer in law, she lives in West Yorkshire.
She stood as a Veritas candidate in the General Election for Bradford South in 2005.
No date has been set for the by-election. Usually a new writ is moved within three months of a vacancy occurring, but there have been a few instances of seats remaining vacant longer than six months before a by-election was called.
Jo Cox's funeral cortege passes through Batley
Traditionally the chief whip of the political party whose MP held the vacant seat will begin the procedure for a by-election.
But the English Democrats spokesman said he thought it may be some time as Labour “have other problems they are trying to sort out” with regards to their long-running leadership issue.
“We are not expecting anything to happen in the next few weeks, but we are ready if it does.”
Mrs Cox, a 41-year-old mum of two, was killed outside Birstall Library on her way to hosting a constituency surgery.
Thousands of people paid their respects on Friday, as mourners gathered in the streets of Heckmondwike and Batley as her funeral cortege passed. She had been an MP for just 11 months and was laid to rest at a strictly family-only service.
An inquest into Mrs Cox’s death was opened and adjourned after hearing she died from multiple stab and gunshot wounds.
Thomas Mair, 52, has appeared at the Old Bailey in London charged with murdering Mrs Cox.
He is also charged with grievous bodily harm, possession of a firearm with intent to commit an indictable offence and possession of an offensive weapon.
He was remanded in custody and is due to go on trial in November.
