Boris Johnson committed a “clear breach” of rules on former ministers taking up new jobs by telling an appointments body he was becoming a Daily Mail columnist only half an hour before the public announcement, the watchdog has said. The former prime minister was unveiled as a new writer for the newspaper, a platform he is expected to use to be a thorn in the side of Rishi Sunak. However, Johnson has become embroiled in a fresh breach of the ministerial code after it emerged that he had waited until almost the last moment before the public announcement to inform the Advisory Committee on Business Appointments (Acoba). A spokesperson said: “The ministerial code states that ministers must ensure that no new appointments are announced, or taken up, before the committee has been able to provide its advice. An application received 30 minutes before an appointment is announced is a clear breach. “We have written to Mr Johnson for an explanation and will publish correspondence in due course, in line with our policy of transparency.” The Mail unveiled Johnson earlier on Friday and said his first column would appear at 5pm, only a day after a damning report found he deliberately misled the Commons and was part of a campaign to intimidate MPs who investigated him. The paper’s announcement was accompanied by a video in which Johnson said the column would be about “exactly what I think about the world”. “It is going to be completely unexpurgated stuff. I am going to be writing whatever I want. I may even have to cover politics from time to time but I will obviously try to do that as little as possible unless I absolutely have to,” he added. Earlier, Eric Pickles, the chair of Acoba, said he would be writing to Johnson to seek clarification on whether he was taking a job as a Daily Mail columnist. Speculation had been prompted by a mysterious promise – made by the Mail on its front page on Friday – that it would be shortly unveiling an “erudite new columnist”. Former ministers who have left the government in the past two years must apply to Acoba before taking up a new appointment or role. Johnson was previously paid a £275,000 salary to write for the Telegraph. He also faced censure from Acoba for failing to seek advice from the committee before joining the Telegraph, after he resigned as Theresa May’s foreign secretary. New rules introduced after work carried out during Johnson’s premiership mean Acoba is consulted as part of the propriety checks on those nominated for honours and peerages, to examine if those in line for them have sought Acoba’s advice in line with the rules. These rules do not apply, however, to those who made the nominations in the first place.