Former British prime minister Boris Johnson, who quit Parliament last week over a finding that he misled lawmakers about Covid lockdown parties, was accused on Friday of a new breach for taking a newspaper columnist job without waiting for required ethics vetting.

Nine months after he left the premiership, Johnson's ethics record is causing renewed trouble for the governing Conservative Party, divided over whether to endorse the findings of a committee of lawmakers that he deliberately misled Parliament over parties at his office during the pandemic.

The committee, which has a Conservative majority, said he should have been suspended from parliament had he not quit as a lawmaker last week. He called it a "political assassination", in a blistering resignation statement in which he also appeared to take swipes at Prime Minister Rishi Sunak.

On Friday, Johnson, 58, was named as a columnist for the Daily Mail newspaper, returning to a journalism career that had seen him write for several leading British titles, including one that sacked him for making up a quote.

"Whether you're a Boris fan or not, it’s going to be required reading – both in Westminster and for millions across the world," the paper said of the column which will appear on Saturdays.

Ministers and civil servants who leave office are required to consult an ethics body, the Advisory Committee on Business Appointments (Acoba), before taking up new jobs. It said Johnson had committed a new breach by failing to give it proper notice.

"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," it said in a statement.

"An application received 30 mins (minutes) before an appointment is announced is a clear breach."

Acoba has no enforcement powers, but a new breach of rules could make it harder for Johnson to mount a political comeback.

Johnson started his working life in journalism, sacked by the Times newspaper for making up a quote. He went on to have a career at the Daily Telegraph, where as a Brussels correspondent he lambasted the European Union in vivid if not always accurate prose.

He later pursued parallel media and political careers as editor of the Spectator magazine and as an MP, and before becoming prime minister wrote a column for the Daily Telegraph. That column often saw him criticised for his views – he was accused of Islamophobia when he said Muslim women who wear burqas looked like letter boxes or bank robbers.