Boris Johnson delivers his final speech as British prime minister outside 10 Downing Street on September 6, 2022.
CNN  — 

UK former Prime Minister Boris Johnson has pulled out of the contest to become the next Conservative Party leader and therefore the next prime minister.

Johnson claimed to have garnered the support of 100 MPs – the minimum number required to clear the threshold to appear on the ballot for the Conservative Party membership – but declined to run, saying “this would simply not be the right thing to do” as “you can’t govern effectively unless you have a united party in Parliament,” according to the PA Media news agency.

His announcement comes after Britain’s former Finance Minister Rishi Sunak officially entered the race to lead the Conservative Party, his second attempt at the position this year.

Sunak has already collected the required 100 nominations from Tory party members in order to run. Sunak had attempted to become leader during the summer following the resignation of Johnson, but lost to Liz Truss who stepped down on Thursday.

A runoff between the two men could have proved divisive for the ruling Conservative party, not least because many of Johnson’s supporters blame Sunak’s resignation in July for sparking the downfall of his government. The Conservatives, in power for 12 years, are currently engulfed in turmoil following the resignations of both Johnson and Truss.

The possible return of Johnson to the top job had split opinions within the Conservative Party, with many lawmakers horrified at the prospect of a second Johnson premiership. He resigned in July following a series of scandals.

The former PM is expected to appear in the next few weeks before the Commons Privileges Committee which is investigating whether he misled Parliament over the parties, which could potentially see him suspended or expelled as an MP.

Rishi Sunak is now clear favorite to be Britain's next prime minister after Boris Johnson's withdrawal from the race.

Sunak declared on Sunday morning that he would be standing in the contest. In a tweet, he wrote, “The United Kingdom is a great country but we face a profound economic crisis. That’s why I am standing to be Leader of the Conservative Party and your next Prime Minister. I want to fix our economy, unite our Party and deliver for our country.”

After Johnson’s Sunday announcement that he would not seek the become the next Conservative Party leader, Sunak tweeted, “Boris Johnson delivered Brexit and the great vaccine roll-out. He led our country through some of the toughest challenges we have ever faced, and then took on Putin and his barbaric war in Ukraine. We will always be grateful to him for that.”

Sunak will be up against Leader of the House of Commons Penny Mordaunt, who said Sunday she regretted the so-called “mini budget” that led to economic turmoil in Britain and the resignation of Truss.

“I very much regret the mini-budget … I raised concerns even before I was in cabinet,” Mordant told the BBC in a Sunday interview, adding there were details about the budget “the cabinet was not aware of.”

The last time the Conservatives held a leadership race – following the demise of Johnson’s government – Truss came first, Sunak second and Mordaunt third.

Graham Brady, the Conservative official responsible for the process, has said any candidate must receive at least 100 nominations from the party’s MPs by 2 p.m. local time Monday.

Truss resigned on Thursday, just six weeks into her disastrous term that pitched Britain deep into political and economic turmoil. Her successor will be the fifth PM to lead the country since it voted for Brexit in 2016.

Amanpour reacts to Truss' claim during resignation speech
02:33 - Source: CNN

Keir Starmer, leader of the main opposition Labour Party, renewed calls for a general election on Sunday, after claiming people are “fed up to the back teeth” with the Conservative leadership and the consequences of their government’s decisions.

“There is a choice to be made. We need a general election! Let the public into decide… Do they want to continue with this utter chaos, or do they want stability under a Labour government?” Starmer asked during a BBC interview.