Downing Street is confident the Prime Minister will still deliver his “living with Covid” plan on Monday despite a delay to ministers approving his proposals.

Boris Johnson’s Cabinet was due to sign off his plan, which includes the axing of the legal obligation to isolate after a positive test, on Monday morning.

But the green lighting of the next step back to normality was pushed back to Monday afternoon, with the delay thought to centre on a request from Health Secretary Sajid Javid regarding how elements of the blueprint will be funded.

Some ministers – including Education Secretary Nadhim Zahawi, Defence Secretary Ben Wallace and Chief Secretary to the Treasury Simon Clarke – had already been photographed arriving at No 10 for the meeting, which was due to start at 10am and would have been the first time the proposals were presented to the full Cabinet.

But it was called off shortly beforehand “so that the Prime Minister could have both a security briefing and have further meetings to finalise the plan on living with Covid”, his official spokesman said.

The spokesman would not be drawn on whether the delay to Cabinet was due to a dispute between the Treasury and the Department of Health.

“I’m not going to get into the nature of (the) discussion of ongoing Government policy,” he said.

But reports suggested that Health Secretary Sajid Javid and Chancellor Rishi Sunak had been in discussions over how to fund the continuation of some free coronavirus testing.

An ally of Mr Sunak insisted the delay was “no one’s fault” but it was “just Cabinet-level discussions as you’d expect”.

Mr Johnson hinted on Sunday that provision for free tests could not continue at their current rate due to the cost of £2 billion a month.

But devolved leaders have condemned any move to scale back the regime.

Welsh First Minister Mark Drakeford said it would be “premature and reckless” to wind back the programme, adding in a tweet: “Testing has played a pivotal role in breaking chains of transmission and as a surveillance tool helping us detect and respond to emerging variants. It’s essential that this continues.”

Scottish First Minister Nicola Sturgeon said that if reports that no new money had been given to carry on testing were correct, it would be “inexcusable negligence given ongoing risks”.

She said: “If Sunak wins, the concern is more than just an end to free access to testing in short term (a decision I don’t agree with) – it’ll also be hard for UK to retain adequate testing capacity for longer term surveillance & response to new variants. Let’s hope common sense prevails.”

In a Westminster briefing on Monday, the PM’s spokesman said he would not be “drawn into getting into exactly what is or isn’t in the plan here and now” when asked by reporters whether free testing is set to come to an end.

But earlier, business minister Paul Scully told Sky News: “If you think what that £2 billion might go towards, there’s a lot of other backlogs in the NHS, other illnesses in the NHS, that that money could otherwise go for.

“So for every person that is worried about a test, there may be another person that’s worried about a cancer diagnosis, for instance.”

The PM’s spokesman said Mr Johnson’s plan is still due to be published on Monday, and that he will address the Commons at around 4.30pm, once a reconvened Cabinet meeting is held.

The delayed meeting, to be chaired by Mr Johnson, is likely to be “a call rather than in-person”, the spokesman said, “because of expedience”.

Mr Johnson will then hold a press conference alongside the chief medical officer for England, Professor Sir Chris Whitty, and chief scientific adviser, Sir Patrick Vallance, at around 6.30pm to 7pm.

Labour’s shadow health secretary Wes Streeting said: “What confidence can the public have that the Conservatives are acting in the national interest when they can’t agree a plan for Covid?

“It is clear the Prime Minister was trying to declare victory before the war is over, simply to distract from the police knocking at the door of Number 10.”

Earlier, Mr Scully said the public should not “work and live under Government diktat for a moment longer than is necessary”.

He told Sky News it is important to make changes to coronavirus rules “to allow the economy to recover, to allow people to get back to a sense of normality, whilst keeping people safe, clearly”.

Mr Scully said: “Infections are coming down quite rapidly, the hospitalisations and deaths are following as well – they tend to lag behind, obviously, the case numbers – but nonetheless you can see the trend within that.”

Mr Scully said Boris Johnson will be “looking at the best advice possible but getting the balance right”.