Former Tory MP Marco Longhi has become the latest Conservative to join Nigel Farage's Reform UK.
Mr Longhi, who served on the Home Affairs Select Committee, claimed Kemi Badenoch's party has been "captured by a "Left-wing influence".
It is another boost to Mr Farage, after a major poll predicted he could win 120 seats in the next election.
Announcing his defection to Reform UK, Mr Longhi said: "Today, I am proud to announce my transition from the Conservative Party to Reform UK, marking a significant step in my commitment to serving the people of our great nation.
"As a longstanding member of the Conservative Party, I have always remained loyal to my principles and values, but above all my dedication to you - the people - has always driven my political career.
"I stand before you as a patriot, reaffirming that I am now truly at home with Reform UK. My loyalty to party leaders started to overshadow my loyalty to you, the people.
"I had to put a stop to this. This decision is about restoring our national identity and prioritising the needs of our citizens over political correctness and elitist agendas.
"The Conservative Party I once identified with - the party of Churchill and Thatcher - has transformed into something unrecognisable, captured by a Left-wing influence that masquerades as conservatism at election time while prioritising the wishes of an elite few when in power.
"In recent years it has repeatedly betrayed your trust and Labour have never earned that trust in the first place.
"I refuse to be part of this 'uniparty drift' towards an ever more Lleft-wing agenda. If I am fortunate enough to represent people again, I will not shy away from the hard truths and necessary actions.
"My commitment to the people was evident when I represented Dudley before and it will remain the same if re-elected.
"I have joined the People's Army, and together, we can make a difference. Let's seize this opportunity for change! Thank you."
Mr Farage reopened his war of words with Mrs Badenoch on Friday as he accused the Tory leader of "crazy conspiracy theories".
The pair have clashed over Reform's membership, with the Tory leader accusing Mr Farage's party of using fake numbers and saying that he "doesn't understand the digital age".
But the Reform UK leader said he was yet to receive an apology, as he prepared to launch a fresh attack on Friday night.
He said: "An apology has not been forthcoming from Kemi Badenoch regarding her crazy conspiracy theories about Reform UK."
She also accused the Clacton MP of "manipulating" the party's supporters on Christmas Day.
The Leader of the Opposition appeared infuriated after Reform UK mocked the Tories by projecting the milestone moment onto CCHQ in Westminster.
The party has more than 166,000 members, overtaking the tally of 131,000.
A new major constituency-by-constituency breakdown of voters reveals Nigel Farage's Reform would scoop 120 seats at the next election, while Labour's number of MPs could plummet to 278.
The mega-poll has been compiled by political strategy firm Stonehaven, which produced the most accurate seat-by-seat projection during the 2024 General Election.
Analysis revealed the party would secure a swathe of seats in eastern England, the North West and the North East.
Luke Betham, head of data science at Stonehaven, said the Government will have to show its plan is succeeding if it is to hold on to the voters that secured its election victory in the summer.
"Immigration is the key issue that is driving them away from Labour," said Mr Betham, before adding: "Labour should start by focusing on where these voters are, not where the party wants them to be.
"The change that was voted for at the last election cannot be realised, in their minds, unless immigration is part of the Government's delivery narrative come the next election."
Such a result would mean senior Cabinet members, such as Deputy Prime Minister Angela Rayner, Home Secretary Yvette Cooper and Energy Secretary Ed Miliband losing their seats, along with Defence Secretary John Healey, Education Secretary Bridget Phillipson and Lisa Nandy, the Culture Secretary.
Responding to the latest set of polling, Reform UK chairman Zia Yusuf claimed his party was "making history and will win the next general election".
He added: "Reform won five seats in July. Six months on this poll shows we would win 120 seats.
"Imagine where we will be in a year, and in four years. The century-long stranglehold the two old parties have had is finally breaking."