Boris Johnson revealed his fears about a lack of ventilators in a telephone call to Donald Trump, the US president has revealed.

The two leaders spoke within hours of the prime minister being diagnosed with coronavirus – and amid fierce criticism of his failure to take up the EU’s offer to jointly obtain the life-saving equipment.

Revealing the contents of the call, Mr Trump said: “I say ‘how are you feeling’ and the first thing Boris said to me is ‘we need ventilators’.”

The US was willing to “help the UK”, despite the gathering crisis in the country, which is now identified as the hotspot of the pandemic, the president said.

The call came after Brussels ridiculed the UK’s claim that a communications mix-up explained its decision not to join an emergency EU scheme to procure ventilators and other desperately needed equipment.

Ministers were at meetings when the offer was made, the EU pointed out – fuelling criticism that ministers put "Brexit over breathing", even as Covid-19 cases soared.

The NHS has only 8,000 ventilators – when 30,000 are likely to be needed – and only a further 8,000 are expected to be ready before the predicted peak of the epidemic, in mid-April.

Mr Trump told a press conference: “We can help the UK – Boris Johnson specifically.

“As you know, Boris, he’s tested, unfortunately he’s tested positive and that’s a terrible thing. But he’s gonna be great, I’m sure he’s gonna be totally great.

“But they want ventilators, Italy wants ventilators, Spain wants ventilators, Germany wants ventilators.”

A Downing Street spokesperson declined to expand on the conversation, beyond saying the leaders had “agreed to work together closely to defeat the coronavirus pandemic”.

The prime minister has spoken with the bosses of a dozen companies he is urging to lead the effort to reach the target of 30,000 ventilators.

However, James Dyson was not among them after Downing Street shot down claims that he had secured a contract to supply 10,000 – because regulatory approval has not been secured.

Words at the window: Social isolation and the Coronavirus Show all 12 1 /12 Words at the window: Social isolation and the Coronavirus Words at the window: Social isolation and the Coronavirus Agnetha Septimus, Matthew Septimus, and children Ezra and Nora Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Husband and wife filmmakers, Claire Ince and Ancil McKain pose for a portrait for the series by Shutterstock Staff Photographer, Stephen Lovekin, shot around the Ditmas Park neighborhood of Brooklyn, New York Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Khadijah Silver and son Eliot Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Anna Beth Rousakis and daughter Mary Rousakis Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Mike Pergola and Denise Pergola with children Henry, Jack, and Will Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Artist Shirley Fuerst Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Jean Davis and Danny Rosenthal, with children Simone, Naomi, and Leah Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Robert E Clark Jr Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Lisa Draho and Josh Zuckerman, with children Ruby and Ava Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Professor and activist Dr Kristin Lawler Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Tom Smith and Laura Ross, with daughters Caroline, Elizabeth, and Abigail Stephen Lovekin/REX/Shutterstock Words at the window: Social isolation and the Coronavirus Callie Lovekin and Lucas Lovekin Stephen Lovekin/REX/Shutterstock

Instead companies including Airbus, McLaren, Ford, Rolls-Royce, Babcock, Siemens and Renault are involved.

No 10 initially said it did not join efforts because “we are no longer members of the EU”, before backtracking after criticism.

It then claimed the UK had missed the procurement deadline due to a “communication problem”, which meant the country was not invited to apply in time.

But a European Commission spokesperson said: “The member states’ needs for personal protective equipment have been discussed several times in the meetings of the health security committee where the UK participated.