Why Dominic Cummings is going

Advisers are meant to be seen, not heard. There has, however, rarely been a political aide more visible than Dominic Cummings.

He first became particularly known to some for his role as the chief of the campaign to leave the EU, then again as Boris Johnson's provocative senior adviser.

But then he found notoriety - and became known to a much wider public who wouldn't always know Westminster figures when, during lockdown, it emerged that the close aide of a prime minister who told people to "Stay at home, save lives, protect the NHS" had made a journey of hundreds of miles from London to Barnard Castle.

Now after boiling tensions in No 10, Mr Cummings is on his way out.

He wrote last year he hoped to make himself "redundant" by the end of 2020 and told me late last night that is what he will do.

There's no question the announcement of his departure by the end of the year was accelerated by turmoil in No 10 in recent days - a swirl of split loyalties and factions.

• Top Johnson aide quits amid infighting at No 10

• Cummings to leave No 10 role by Christmas

A No 10 insider told me Mr Cummings "jumped because otherwise he would be pushed soon", suggesting that, in the last few days, the prime minister saw that the former Vote Leave team was just "in it for themselves".

Indeed, for many Conservatives, Mr Cummings' departure, alongside that of Lee Cain, the former director of communications, brings a chance for a reset.

One member of the Cabinet even told me Mr Cummings' exit was a "blessing".

And yet Dominic Cummings was valued hugely by Boris Johnson - one of the relentless architects of the prime minister's path to a hefty majority.

One adviser told me it was a "huge error to let him go" - it would allow the Tories to "regress to being a party of rich southerners and MPs nodding along".

It was perhaps inevitable that the Vote Leave tribe would fight so hard they hurt themselves in the process.

Loved by some, loathed by others, the departure of the Vote Leave duo represents a big change at the highest level of government - Boris Johnson losing two of his aides who became controversial but who were also key to creating the political version of him.