Richard Tice has claimed the Rochdale by-election was not “free and fair” after Reform UK’s candidate and campaigners allegedly suffered abuse and death threats.

The Reform UK leader also questioned a sharp rise in the number of postal votes cast, saying they were “unquestionably open to significant abuse”.

In an angry speech at the count in Rochdale leisure centre he reeled off a series of allegations about the mistreatment of his party’s campaign team.

Simon Danczuk, a former Labour MP for the Greater Manchester town, has been representing Reform UK in an ill-tempered by-election battle.

Mr Tice said that Mr Danczuk and his team had been “subjected to death threats” and “suffered vile racist abuse” during the campaign.

He added that they had been “refused entry to hustings in a public building” and “suffered daily intimidation and slurs”.

“The behaviour of certain candidates and their supporters in this contest fell very far short of our traditional democratic standards,” he said.

“What we have witnessed and experienced in Rochdale is deeply disturbing,” he added, saying that the conduct “has implications for our democracy”.

In a video message sent to Mr Danczuk a man allegedly referred to the Reform UK candidate as “a white devil” and threatened to “put one in his head”.

Greater Manchester Police said on Tuesday that it had arrested a 23-year-old on suspicion of malicious communication.

Mr Danczuk was refused entry to a hustings on Thursday, February 22 after only some candidates were invited in what was described as “an affront to democracy”.

Mr Tice claimed that in one incident on the campaign “Reform UK business supporters were threatened with a firebomb attack if they distributed our leaflets”.

He added that “menacing behaviour” had been “a feature of the entire campaign” including “outside polling stations on the day of the election itself”.

Reform UK had positioned itself as a party fighting on domestic issues in a by-election that was heavily focussed on Gaza.

George Galloway, the leader of the Workers Party, was widely expected to win the seat after campaigning on a relentlessly pro-Palestine platform.

Mr Tice also raised questions over the sharp rise in the number of people casting postal votes, which he said were open to abuse.

He said that the number of postal votes had risen from 14,000 at the 2019 General Election to 23,000, despite a 20pc lower turnout in the by-election.

“In this ugliest of contests, we are concerned by the sudden increase in the size of the postal vote,” he said.

“The results of the Rochdale by-election should act as a stark wake up call to those in power – and the entire electorate. This is Britain.

“We are supposed to be a beacon of democracy. This shameful contest has been more characteristic of a failed state.

“Unless something dramatic changes, our fear is that it will be repeated in dozens of constituencies across the UK at the general election.

“By Christmas, we face the prospect of numerous extremist anti-Semitic lawmakers in the House of Commons.”

There is no indication of any significant voting irregularities in Rochdale.

The Electoral Commission has said the UK has “low levels of proven electoral fraud” with 93 per cent of complaints registered in 2022 not resulting in police action.