Mr Cummings becomes the latest member of the Downing Street inner circle to either be diagnosed with Covid-19 or be forced to self-isolate as a result of noticing symptoms associated with the deadly virus.
Boris Johnson, Health Secretary Matt Hancock and the UK’s Brexit negotiator, David Frost, have all been struck down with coronavirus, while chief medical officer Professor Chris Whitty has quarantined himself after noticing symptoms.
Scotland Secretary Alister Jack, who sat between Conservative Party leader Mr Johnson and Mr Hancock at Prime Minister’s Questions on Wednesday, confirmed at the weekend that he has a cough and a temperature – tell-tale signs of coronavirus – and would remain at home, making him the third Cabinet minister to shut themselves away.
Mr Cummings, the mastermind behind Vote Leave’s messaging at the EU referendum, was last seen running out of Number 10 shortly after Mr Johnson posted a video message on Friday announcing he had tested positive.
A Number 10 source told the PA news agency that the 48-year-old noticed symptoms of Covid-19 over the course of the weekend and had decided to self-isolate.
He will continue to stay in contact with the Downing Street team while in isolation, the source added.
Father-of-one Mr Cummings has proved a controversial figure, both before and after his appointment by Mr Johnson.
Downing Street last week denied suggestions that the PM’s top aide had been prepared to let the elderly die to protect the economy during the UK outbreak of coronavirus.
Number 10 branded as “highly defamatory” a Sunday Times report which claimed that Mr Cummings supported so-called “herd immunity” even if it meant older people died.
In February, Mr Cummings, responsible for the winning “Take back control” Brexit slogan in 2016, sacked one of former chancellor Sajid Javid’s chief aides without Number 11’s knowledge and, before the PM’s reshuffle, suggested cartoon characters would be more competent than the crop of Cabinet ministers in place at the time.
As of Sunday, there were 19,522 positive cases in the UK and 1,228 of those admitted to hospital with Covid-19 had died.