Writing in the Daily Telegraph on Tuesday, Clarke claimed Sunak, who is under increasing pressure after he was dealt a blow to his Rwanda deportation plan in the House of Lords, was "leading the Conservatives into an election where we will be massacred".
Although Conservatives are traditionally protective of British institutions, some Tory MPs have recently broken rank to criticise their work.
Last week, The Conservative Party witnessed its biggest rebellion in years after 60 MPs called on Rishi Sunak to tighten his grip on the Rwanda legislation.
Asylum seekers respond to Sunak's relentless emergency Rwanda policy after it was passed by an overall majority vote on Wednesday.
Sunak spent the morning urging his peers in the unelected chamber to pass his asylum bill as soon as possible, arguing it was the "will of the people" and they should see it as a "priority" for the country.
Sunak could face a humiliating defeat that could cost the Conservative Party its next general election win if Tory MPs continue to vote for Rwanda policy amendments.
Two deputy chairmen of the Conservatives resigned from their roles as they joined dozens of Tory right-wingers in backing amendments to toughen the scheme.
The bill in its current form is due to be debated and voted on in Parliament today, setting Sunak on a collision course with both factions of his party.
Sunak has said he plans to hold an election later in the year, which is widely expected to be in October or November, as a YouGov survey of 14,000 respondents forecasts that The Tories will hold on to just 169 seats, while Labour will claim 385.
While Rishi Sunak continues to push his emergency Rwanda Treaty, Keir Starmer is considering processing asylum applications from overseas.
Sunak's strategy to cut this figure is centred around sending migrants to Rwanda – but this plan was blocked by the Supreme Court last month.
Despite the primary purpose of immigration detention being to facilitate deportations, the annual IMB report highlighted that the majority of detainees were ultimately released.
Despite several humanitarian concerns, Rishi Sunak's emergency Rwanda legislation was passed by an overall majority vote in the House of Commons this week.
The substantial payment was made in April of this year, the Home Office's top civil servant said in a letter to MPs, after £140m had already been sent to the African nation.
Cleverly said there was now no "credible" reason to block the deportation flights because the treaty addressed all the issues raised by the Supreme Court
Immigration Minister Robert Jenrick confirms emergency Rwanda treaty and says flights will take off "as a matter of urgency".
Prime Minister Rishi Sunak made the change after firing Suella Braverman as Home Secretary, following her controversial comments on the police last week.
The UK government have taken the Rwanda bill to the Supreme Court, despite the deportation plan being ruled 'unlawful' by the Court of Appeal in June.
The UK government partners with tech companies to "clamp down" on refugee-related smuggling content on social media.
The revelation is part of an Impact Assessment of the Government's new Illegal Migration Bill, which was introduced to Parliament in March.
Interior minister Suella Braverman visited Rwanda on Saturday to expand a deal under which the country will accept migrants who arrive in Britain without permission, if British courts confirm that the proposals are legal.
The Eritrean woman travelled through several countries before crossing from France to the UK in a flimsy boat, hoping to find safety.