Boris Johnson unveiled as new Daily Mail columnist

Boris Johnson has been signed up to write a column for the Daily Mail, one of his biggest newspaper supporters.

The Mail said the first column by the former prime minister, for Saturday's paper, would appear online this evening.

It has emerged that Mr Johnson has not cleared the job with the watchdog that vets former ministers' appointments.

The Advisory Committee on Business Appointments (Acoba) is looking into whether he has broken the rules.

The Daily Mail Online Twitter account described him as "one of the wittiest and most original writers in the business".

In a video shared by the paper, he said: "I am thrilled to have been asked to contribute a column to the Daily Mail.

"It is going to be completely unexpurgated stuff.

"I may even have to cover politics, but I'll obviously try to do that as little as possible unless I absolutely have to."

The clip also features a compilation of shots of Mr Johnson in Downing Street, the House of Commons and out jogging.

An Acoba spokeswoman said the committee had written to Mr Johnson as it had not received an application from him.

She said "newspaper columns are not considered significantly problematic", but he was still required to seek advice.

Former ministers are meant to apply to Acoba before taking up a new appointment or role for up to two years after leaving government.

The committee has no powers to punish MPs - or former MPs - who have broken the rules over taking up jobs but can issue public rebukes.

Acoba chairman Lord Eric Pickles will be writing to Mr Johnson to seek clarification on whether he is taking the job.

The committee previously found Mr Johnson broke the rules after taking up a £275,000 a year column with the Telegraph weeks after standing down as foreign secretary.

The watchdog said it was "unacceptable" Mr Johnson had not sought its advice before signing the contract.