Britain’s defence chief has insisted it is “business as usual” amid concerns over who has the authority to take major decisions in Boris Johnson’s absence.

General Sir Nick Carter, chief of the defence staff, said he believed there is a “very clear” chain of command given the National Security Council (NSC), containing senior Cabinet ministers, is “wrapped around” the Prime Minister.

He suggested operations would continue without disruption despite Mr Johnson being admitted to intensive care after his coronavirus symptoms worsened.

Cabinet Office minister Michael Gove said he could not comment about national security matters when asked if responsibilities connected to nuclear attack had been passed on to Foreign Secretary Dominic Raab, who is deputising for the PM.

In a separate interview, he claimed “Dominic is in charge” before outlining how there are “appropriate ways” to take decisions to keep the country safe.

Conservative Tobias Ellwood, chairman of the Defence Committee, was among those seeking information as he wrote on Twitter: “It is important to have 100% clarity as to where responsibility for UK national security decisions now lies.

“We must anticipate adversaries attempting to exploit any perceived weakness.”

Sir Nick said all the thoughts and prayers of the armed forces are with the PM.

Asked if there is a clear chain of command for the armed forces in such a situation, Sir Nick told BBC Radio 4’s Today programme: “Yes, it’s very clear I think.

“We work straight through to the Prime Minister but of course there’s the National Security Council that’s wrapped around him and formed of many of the Cabinet ministers and supported by the National Security Adviser.

“I think on that basis we’re pretty confident it’s business as usual as far as the operations are concerned.”

Sir Nick said he believed Mr Raab would chair the NSC and be supported by others.

Asked if he still believed six months was a reasonable timescale for the armed forces involvement in the coronavirus operation, Sir Nick replied: “I think that was a reasonable assumption a month ago and I think we’re all playing each day as it comes at the moment.”

Pressed on what the armed forces would do if there was civil unrest in the country, Sir Nick replied: “I think it’s most unlikely that we would get involved in public order at all.

“Generally speaking our role in this is to back-fill the police in those roles that don’t face the public so the police force are able to manage public order on the country’s behalf.”

Mr Gove, asked who is in charge in terms of defences and security, told Good Morning Britain: “Dominic is in charge.

“I won’t go into the details of the different national security decisions and protocols that there are but there are appropriate ways in which decisions can be taken in order to keep this country safe.

“The ultimate decisions are always taken by politicians and in this case the PM has asked Dominic to deputise for him, so it’s Dominic as Foreign Secretary who’s in charge.”