DOWNING Street has insisted Boris Johnson would step down as Prime Minister once a new Tory leader is chosen after he reportedly told a supporter he wants to carry on.

Lord Cruddas of Shoreditch, a former Tory party treasurer who has started a petition to put Mr Johnson on the ballot paper alongside Rishi Sunak and Liz Truss, said the PM “definitely does not want to resign” and believes he might be able to stay in No10.

He said Mr Johnson had personally invited him to lunch at Chequers last Friday and told him that he was “rooting” for his campaign to succeed.

Lord Cruddas, who has given the Tories more than £3million, told the Telegraph: "Boris thanked me for my 'Boris on the ballot' campaign. He said he was enjoying following it and he wished me well.

"He said he could understand the membership's anger at what had happened. He said that he wished that he could carry on as Prime Minister. He said he does not want to resign."

Asked by the peer if he would "wipe away" his resignation immediately with "a magic wand", Mr Johnson reportedly replied: "I would wipe away everything that stops me being PM in a second."

Mr Johnson resigned in disgrace on July 7 after a rebellion by his cabinet and MPs over his lack of personal integrity and a series of scandals.

However, and despite opposition warnings he might cause trouble by not going immediately, he is not due to leave Downing Street until after the leadership winner is announced on September 5.

Lord Cruddas added: "He wants to carry on to finish the job. He wants to fight the next general election as leader of the Conservative Party.

"He also said that if there was a general election tomorrow and he was leader of the Conservative Party, he would win a general election, and I agreed with him.

"He has taken inspiration from my campaign. He hopes that there will be a way for him to stay on as Prime Minister and he believes that the Conservative Party will be making a big mistake if they ignore the wishes of its membership."

Responding to the comments, a No10 spokeswoman said: “The Prime Minister has resigned as party leader and set out his intention to stand down as PM when the new leader is in place.”

The intervention added to the sense of ill-discipline around the leadership race, which was today branded “puerile” and “embarrassing” by a Tory minister after a row broke out over Mr Sunak's wardrobe choices.

Cabinet Office minister Johnny Mercer said the rival campaigns should remember that on the “current trajectory” the Tories would be out of power in two years’ time, and it was “time to raise standards”.

It followed Culture Secretary Nadine Dorries, a supporter of the Foreign Secretary, attacking Mr Sunak over his expensive clothing.

She tweeted a link to a Daily Mail story about the millionaire former Chancellor wearing a bespoke Henry Herbert suit worth around £3,500, as well as recently wearing Prada loafers to a building site in Redcar. 
Suggesting his huge personal wealth meant he was out of touch with voters,

Ms Dorries said Ms Truss would be "travelling the country wearing her earrings which cost circa £4.50 from Claire Accessories. Meanwhile…
“Rishi visits Teesside in Prada shoes worth £450 and sported £3,500 bespoke suit as he prepared for crunch leadership vote.” 
Guildford MP Angela Richardson, a supporter of Mr Sunak, replied: “FFS [for f***'s sake] Nadine! Muted.”

It later emerged that Ms Dorries previously boasted of having a £6,000 pair of diamond earrings and told reporters “I don’t skimp on jewellery”, even designing her own bespoke pieces.

Reacting to the spat, Mr Mercer tweeted: “Back in Whitehall today - perhaps only a few weeks to make a difference. 

“Probably worth remembering that on current trajectory we are out of power in two years time. The puerile nature of this leadership contest is embarrassing. Time to raise the standards."