Ex-Conservative Party deputy chairman Lee Anderson has defected to Reform UK.
The defection ends weeks of speculation about the Ashfield MP and TV presenter’s future.
Mr Anderson said he had been given the chance to “speak out in Parliament on behalf of millions of people up and down the country” who support Reform.
Speaking at a press conference, Mr Anderson said he was “prepared to gamble on myself” because he said he knew “how many people support Reform and what they have to say”.
“All I want is my country back,” he added.
Reform UK founder and honorary president Nigel Farage said called the defection “huge”. He said: “I don’t think Westminster really understands this yet.”
Mr Anderson ruled out calling a by-election in his own seat, telling the BBC it “would be pretty reckless for me to suggest a by-election when we could have a general election in May”.
Two years ago, Mr Anderson backed a failed bid to let constituents trigger a by-election when their MP changes parties.
Home Secretary James Cleverly said Mr Anderson had “made a real mistake” in defecting from the Conservatives.
“Reform is not the answer,” he added.
Mr Cleverly said he agreed with Mr Anderson’s comments from January this year, when he said a “vote for Reform will only let the Labour party in”.
Mr Anderson was elected in 2019 to the Red Wall seat of Ashfield with a 5,700 vote majority – having previously served as a Labour councillor for his home town.
The son of a coal miner, Mr Anderson belonged to Arthur Scargill’s National Union of Mineworkers. His first job in politics was working in the office of local Labour MP Gloria De Piero, serving as district councillor at the same time.
After switching to the Conservative Party, the staunch Brexit supporter became an ally of former prime minister Boris Johnson.
He was made deputy chairman of the Conservative Party in February last year, but resigned in January to rebel against Rishi Sunak’s Rwanda bill.
Announcing Mr Anderson’s defection, Reform UK Leader Richard Tice said his party had founds a “champion” for its plans to supplant the Conservatives in the Red Wall.
Mr Anderson was a “person of great integrity”, Mr Tice added.
The Reform leader said: “I think millions of British people endorsed the concerns and sentiments of what Lee was saying, which is that we are sick and tired of our streets being taken over by these pro-Hamas, extremist, antisemitic people and Islamist extremists.”
Reform UK has confirmed he will stand for Ashfield in the general election, superseding Henry Grisewood – who the party had initially chosen.
Ex-miner Lee Anderson joined the Conservative Party having previously worked for a Labour MP
Pat McFadden, Labour’s National Campaign Coordinator, said Mr Anderson’s defection showed “the Conservatives are falling apart”.
“The truth is that the prime minister is too weak to lead a party too extreme to be led,” he said.
Some of Mr Anderson’s former colleagues criticised his defection – saying it made “a less conservative Britain more likely”.
The New Conservatives, made up mostly of 2019 Tory Red Wall MPs like Mr Anderson, said “the responsibility for Lee’s defection sits with the Conservative Party”.
In a statement, the group argued the Tory party’s failure to stick to the promises of the 2019 general election had led to split in the party.
Mr Anderson sparked a backlash after he claimed last month that the capital had been “taken over” amid the weekly pro-Palestinian protests over the war in Gaza.
In an interview with GB News, Mr Anderson said: “I don’t actually believe that these Islamists have got control of our country, but what I do believe is that they’ve got control of Khan, they’ve got control of London.
“He’s actually given our capital city away to his mates.”
Mr Anderson was stripped of the Tory whip after he refused to apologise for the remarks. He instead doubled down on his comments although conceded his phrasing was “clumsy”.
Analysis by BBC chief political correspondent Henry Zeffman
Lee Anderson’s decision to join Reform is unquestionably a significant blow for Rishi Sunak and the Conservatives.
Despite having no MPs and just a small handful of councillors, Reform are reliably polling around 10%. That is a high enough figure that some Conservative MPs believe it is as important for them to win back voters they are losing to Reform as it is those who are switching to Labour.
By giving Reform a parliamentary figurehead for the first time, Mr Anderson may make it harder for the Conservatives to reunite the right.
There are some important caveats. Most importantly, Mr Anderson is not making his defection from a position of strength. He was suspended from the Conservative ranks at Westminster after accusing Sadiq Khan, the mayor of London, of being controlled by Islamists.
Mr Anderson refused to apologise for his comments, making his suspension all but inevitable. There was grumbling from some Conservatives who wanted Mr Anderson to be handed a clear path back into the fold – but any such route would almost certainly have required him to apologise, which he again refused to do today.
It’s also worth noting that while Mr Anderson is well-known in Westminster for his pugnacious style, and has a show on GB News, he is not exactly a major national figure. Arguably a more worrying announcement for the Conservatives would have been the return of Nigel Farage to active campaigning duties.
Yet one person who definitely does rate Mr Anderson’s ability to connect with a slice of the British public is the prime minister himself. Mr Sunak appointed Mr Anderson a deputy chairman of the Conservative Party in February last year. And as recently as January Mr Anderson starred with him in a campaign video about how “we should be so proud of our country”.