Ruth Davidson doubts George Osborne's ability to remain an MP Ruth Davidson doubts George Osborne's ability to remain an MP George Osborne: not fake news, just a fake editor I feel sorry for the people of Tatton – I hear their MP is just too busy to care | Jess Phillips

Ruth Davidson said after spending 10 years as a journalist and six as a politician she was not sure she could combine them both.

The leader of the Scottish Conservatives has questioned George Osborne’s vow to remain as an MP after he becomes editor of the London Evening Standard, as the chair of the parliamentary standards watchdog pledged to review rules on MPs’ second jobs.

Ruth Davidson said she could not see how the former chancellor could juggle being a journalist and a politician.

“I spent 10 years as a journalist and I’ve now spent six years as a politician and I’m not sure I could combine them both,” she told the BBC’s Andrew Marr Show. “I work a pretty busy week as it is and this week in particular. I’m not sure I could do both at the same time if I’m honest.”

The MP for Tatton now has a total of six highly paid jobs including his constituency work, as: editor of the Evening Standard; chair of the Northern Powerhouse partnership; adviser to BlackRock; a Kissinger fellow in the US; and an after-dinner speaker.

However, on Sunday Osborne’s new job was defended by both the former prime minister Tony Blair and ex-cabinet minister Nicky Morgan, both prominent remain campaigners who hinted they were pleased someone of his political persuasion was in the post.

George Osborne: I can balance my new editorship with job as MP – video

“I don’t know if having both of those jobs is doable, but it’s a great thing for the Evening Standard,” Blair told Marr. “Why not? He’s a highly capable guy and it’ll make politics __more interesting.”

Morgan, who co-wrote a piece for the Observer on Sunday opposing grammar schools, said the appointment proved there was still an appetite for liberal conservative voices.

“When you are fired, as we all were last summer, what did the government expect? That we were going to just all disappear?” she told ITV’s Peston on Sunday. “We are going to make our voices heard, whether it’s me writing articles, or George being editor.

“There’s a liberal conservative point of view to be talked about and we are going to do that.”

The comments came as the chair of the country’s chief standards watchdog said rules regarding MPs’ second jobs may need to be reviewed, given Osborne’s decision not to resign as MP for his Cheshire constituency, which is almost 200 miles from London.

Lord Bew, chair of the committee on standards in public life, told the Sunday Times the current rules were “getting into rockier waters”.

“We have not ruled out MPs having second jobs, quite deliberately, up until now, but we now have to look again at our rules,” he said. “We are going to discuss whether our rules on second jobs need to be changed in light of this.”

Osborne’s case raised the “issue of how much time MPs have to devote to their parliamentary work,” Bew said.

Labour’s elections chief, Andrew Gwynne MP, has written to the Cabinet Office to raise concerns about the potential conflict of interest in Osborne taking the role while remaining an MP. Former shadow business secretary Clive Lewis has also written to the advisory committee on business appointments (Acoba), saying the committee should rebuke Osborne for accepting the post before he had written to the committee for guidance.

Acoba assesses any private paid roles taken by former ministers and civil servants in fields they used to regulate in government, but although it can offer guidance, it cannot prevent appointments. Its advice has historically included guidance to delay appointments, which it cannot do if the appointment has already been announced.

Osborne has previously been rebuked by Acoba for announcing his Northern Powerhouse initiative before seeking the committee’s advice, and is likely to be similarly criticised by the watchdog for publicly announcing his newspaper job having only informed the committee earlier this week.