Boris Johnson’s ex chief of staff is plotting a startup political party to take on the Conservatives in the election after next.

Dominic Cummings has said it is “time to build a startup” to “replace the rotten Tories and win in 2028”.

But a Tory critic dismissed the plan, telling The Times it was “yet more mad ramblings from a narcissistic egomaniac who is thankfully becoming increasingly irrelevant”.

Mr Cummings, who was Mr Johnson’s most senior advisor, said Rishi Sunak is the hardest-working MP with the highest IQ, but has “no grip of power, no governing plan, no message and no political strategy worth spit”.

Writing for subscribers to his blog, Mr Cummings said he is already receiving messages from MPs and donors asking how to rebuild the party.

“This is the time to start building the replacement so that from 2200 on election night in October-December 2024 the old Party is buried and a new set of people with new ideas start talking to the country and can take over in 2028 and give voters the sort of government they want and deserve,” Mr Cummings said.

His agenda is similar to the agenda he wanted to pursue in Downing Street with Mr Johnson, being “tougher” on crime, security and immigration and pulling out of the European Convention on Human Rights.

It would also freeze or cut taxes for working people, reduce the size of the state and close tax loopholes which benefit the wealthy.