The Tory leadership debate on Sky News planned for Tuesday night has been cancelled after Rishi Sunak and Liz Truss said they did not want to take part, the broadcaster said.
The cancelled debate comes amid despair from Conservative MPs at the increasingly divisive and bitter contest.
ITV's leadership debate on Sunday night was described by ITV News Political Editor Robert Peston as a "disaster" for the party.
In a statement, Sky said: “Two of the three candidates currently leading in the MPs ballots, Rishi Sunak and Liz Truss, have confirmed to Sky News that they do not want to take part.
“Conservative MPs are said to be concerned about the damage the debates are doing to the image of the Conservative Party, exposing disagreements and splits within the party.
“Both are very welcome to taking part in future Sky News televised debates."
Labour leader Sir Keir Starmer said he was “astonished” by Tory leadership candidates withdrawing from the televised debate, saying it demonstrated a lack of “confidence”.
The leadership contenders have already taken part in debates on Channel 4 and ITV which have seen the would-be prime ministers taking primetime pot shots at each other
The remaining five candidates were involved in series of bad-tempered exchanges in Sunday night's debate on ITV as the battle for a place in the run-off ballot of party members became ever more bitter.
Contenders for the Tory leadership will be whittled down to just four on Monday as MPs cast their votes in the third round of the contest to find a successor to Boris Johnson.
Former chancellor Mr Sunak, who topped both the first two ballots, clashed with international trade minister Penny Mordaunt and Ms Truss over the economy.
And former equalities minister Kemi Badenoch and Tom Tugendhat – who finished fourth and fifth respectively in the last ballot and are battling to avoid elimination – squared off over who had the record and experience to be prime minister.In Westminster WhatsApp group messages, seen by ITV News Deputy Political Editor Anushka Asthana, Tory MPs warned about the damage the in-fighting could do to the party.
In a message seen by ITV News, one MP warned: "The division, smears and personal attacks this weekend have been disgraceful. Nothing will kill our party more than blue on blue."
On a visit to a central London bank Sir Keir told reporters: “I’m astonished that those that want to be prime minister of the United Kingdom are pulling out of debates and out of scrutiny.
“I can see based on what I’ve seen in the debates so far why they want to do so because this is a party that is out of ideas, out of purpose, they’re tearing each other apart.
“And I think for millions of people, particularly with the heatwave today, they’ll be saying I want a government that’s focused on the day job, that’s getting on with resilience for today and tomorrow, however long this heatwave goes on, and focused on the cost-of-living crisis.”
He added: “Pulling out of a TV debate when you want to be prime minister doesn’t show very much confidence”.
Angela Rayner MP, Labour’s Deputy Leader, also accused the Conservatives leadership hopefuls of "hiding from scrutiny".
“This Conservative ‘leadership’ contest is so embarrassing they’ve cancelled the debate - so you can’t see them fighting like rats in a sack," Ms Rayner said. She added: “The country deserves better than Tory candidates hiding from scrutiny simply because their first two performances have shown they would be a danger to the economy and the future of the UK“This is a hopelessly divided Tory party, one that has racked up over £300 billion in unfunded promises and yet still has no plan to get to grips with their cost of living crisis. Only a Labour government can give Britain the fresh start it needs.”
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Ms Mourdant came under fire on Monday from her boss who claimed she missed ministerial meetings because she was plotting her Tory leadership bid.The trade minister’s absence from meetings forced colleagues to pick up the pieces, International Trade Secretary Anne-Marie Trevelyan alleged in a scathing attack on the leadership hopeful. The Cabinet minister is backing Mr Tugendhat who is at risk of being eliminated from the contest in the next round of voting later on Monday.A series of votes among Tory MPs this week will narrow the field down to a final two, who will then face a summer of campaigning for the support of party members in a final vote.
The new leader will be announced on September 5 and is expected to become prime minister the following day.