Boris Johnson is “on the mend in a big way” but his return to work from his coronavirus convalescence is a matter for the doctors, the Health Secretary has said.

Matt Hancock described the Prime Minister on Friday as being in an “ebullient” state while recovering at his Chequers country retreat, where he is said not to be undertaking official work.

Downing Street sources were dismissing reports that Mr Johnson was preparing to return to No 10 as early as Monday, saying a decision was yet to be made.

But there were indications that he was preparing to resume duties with him holding an audience with the Queen and talking to Donald Trump, who described Mr Johnson as “ready to go”.

Mr Hancock insisted the PM “has to be better” before returning to Downing Street and refused to get into the “precise timing” of his recovery.

“I spoke to him yesterday, he’s cheerful, and he’s ebullient and he’s definitely on the mend in a big way. When exactly he comes back is a matter for him and his doctors,” he told BBC Radio 4’s Today programme.

Meanwhile, Mr Johnson’s sister Rachel Johnson has described the time he spent in intensive care as “very frightening” and “terribly scary” for the family.

Speaking on her new LBC radio show, she paid tribute to the NHS and thanked nurses Luis Pitarma and Jenny McGee for the care they gave the PM.

She said: “Jenny – I’m so pleased and I would like to thank you personally, but I can’t, so just accept my thanks from the entire Johnson family, and to Luis and to everybody in the ICU at St Thomas’ for everything you did to keep my brother safe. Thank you very much indeed.”

After seven nights in hospital with Covid-19, three of which were spent in intensive care, Mr Johnson began his convalescence at Chequers on April 12.

Downing Street has said he is not undertaking official Government business but this week has held a telephone audience with the Queen and spoke to the US president.

The PM’s official spokesman declined to say when Mr Johnson would return to work, and said he was still not reading his briefing papers in the usual way.

“In terms of when he is actually able to get back to work in Number 10 he will take the advice of his medical team on that,” the spokesman said.

Mr Trump, at a White House briefing on Thursday, said he was “actually surprised” at how “incredible” the PM sounded in their call two days earlier.

“He was ready to go. I’m very surprised to tell you this. He’s like the old Boris – tremendous energy, tremendous drive,” the president said.

Mr Johnson has also spoken to Foreign Secretary Dominic Raab, who is deputising for him, and is being sent regular updates on Government business.

But a timetable for his official return to act on that business and to take charge of a country in lockdown and struggling through its gravest crisis in generations does not appear to be determined.

A No 10 source said: “The PM will follow his doctor’s advice and it is unhelpful to speculate at this stage.”