The row over Matt Hancock’s use of a private email account has led to questions for Boris Johnson over his own communications.

Former health secretary Mr Hancock has been accused of using a private Gmail account to conduct government business, something denied by No 10.

But the Prime Minister was targeted by Labour after refusing to be drawn on whether he also used a personal email account for work purposes.

“I don’t comment on how I conduct Government business,” Mr Johnson said.

“But I can tell you that we in this Government are getting on with focusing on the people’s priorities.”

Mr Johnson’s former aide Dominic Cummings suggested the Prime Minister and Mr Hancock routinely used WhatsApp message instead of official communications channels.

And deputy Labour leader Angela Rayner warned that if Mr Johnson was using a personal email account for Government business it would be “rank incompetence” which could put national security at risk.

The Sunday Times reported that minutes of meetings revealed that Mr Hancock had been using a private email address since March 2020, which meant that key decisions and their reasoning were not recorded or could be difficult to access for any future inquiry into the handling of coronavirus.

The minutes from a meeting between senior officials in the department in December reportedly showed that David Williams, who was then the department’s second permanent secretary, warned that Mr Hancock “only” dealt with his private office “via Gmail account”.

The Sunday Times reported that Mr Williams said “the SOS (secretary of state) does not have a DHSC inbox” and that health minister Lord Bethell also “routinely uses his private inbox”, but that official accounts had been provided afterwards.

He said he “doesn’t believe there was inappropriate acts on behalf of ministers but can clearly see the optics suggest otherwise”.

The Prime Minister’s official spokesman said: “Both the former health secretary and Lord Bethell understand the rules around personal email usage and only ever conducted Government business through their departmental email addresses.”

The spokesman suggested Mr Hancock’s use of a Gmail account was “related to things like diary acceptances”.

But Cabinet Office minister Julia Lopez told MPs: “At the time at which we’re in the height of the pandemic, a huge volume of correspondence was coming to ministers via their personal email addresses, to their parliamentary email addresses, to their ministerial email addresses.”

There were “15,000 offers of help in securing PPE that came in following the Prime Minister’s call for assistance”, she told the Commons.

Mr Cummings suggested Government business was discussed on WhatsApp rather than government email accounts.

Responding to the claim that Mr Hancock and Lord Bethell “only ever” conducted departmental business on their official email accounts, Mr Cummings said: “Except for all the WhatsApps between PM, MH and Tory donors which No 10 officials know exist cos they’re copied in to some.

“So dozens of No 10 officials know No 10 press office openly lying again.”

For Labour, Ms Rayner seized on Mr Johnson’s response to questions about his own email use.

“If the Prime Minister is using a personal email account for government business his rank incompetence and disregard for the rules is putting sensitive information and national security at risk, leaving our country wide open to attack from hostile actors,” she said.

The Labour frontbencher called for an independent inquiry into the working practices of ministers and the security risks created by the use of personal email accounts.

Shadow health secretary Jonathan Ashworth suggested Lord Bethell should be “relieved of his responsibilities” for using a personal email account to discuss Government contracts.