Downing Street appeared to reprimand the Tory MP, with a spokesman saying “MPs’ primary job is and must be to serve their constituents”.
Sir Geoffrey told The Telegraph on Sunday night that “as Keir Starmer well knows, many prominent and respected Labour MPs have practised the law exactly as I have while in the House of Commons”.
He added: “It has long been an established principle by successive commissioners that Paragraph 16 of the Code of Conduct must be interpreted with a sense of proportion.
“As long as parliamentary premises are not being exploited to enhance or promote an MP’s private work, there is no net additional cost to the public, and the use is one off or occasional I do not believe it infringes the code.”
Sir Geoffrey said that whether it was an infringement would “be for the Commissioner and the Committee to decide and may need further guidance”.
Ms Rayner stated Sir Keir had given up his certificate to practice, when asked about the Labour leader earning £100,000 in legal fees since becoming an MP.
When asked about Sir Keir advising the government of Gibraltar, Ms Rayner told The Andrew Marr Show: “I do not accept the premise that what Geoffrey Cox was doing, advising a tax haven which is described by the Government as corrupt, and using his office to do that, in any way, shape or form is the same as Keir Starmer doing some legal work when he was first an MP. That is not the same.”
Ms Rayner added: “We’ve said that we’d ban second jobs but there will be some areas like where we’ve got an A&E doctor that’s practising at the moment, so that they can continue to do that.”
Last week Mr Johnson was forced to insist “Britain is not a corrupt country” after a press conference at the Cop26 climate summit was dominated by sleaze claims directed at MPs.
