Healthy adults aged 42 and over in England have been urged to come forward for their Covid-19 jab as the Prime Minister warned that the nation is “not out of the woods yet”.

Boris Johnson raised concerns about new variants of the virus during a meeting of the Cabinet, Downing Street said.

But he told ministers that the road ahead “looks positive”.

It comes after new figures show that deaths involving Covid-19 in England and Wales have fallen 97% since the peak of the second wave of the virus.

A No 10 statement said: “Cabinet concluded with an update on the pandemic.

“The PM reiterated that the data continues to look good but warned that we are not out of the woods yet as variants of concern continue to pose a threat.

“The PM said that while the road ahead looks positive, there will still be challenges and this Government will continue to take tough decisions where necessary to protect both lives and livelihoods.”

It comes after Mr Johnson denied saying he was prepared to let “bodies pile high” rather than order another lockdown, amid a bitter briefing war that has hit Downing Street.

Meanwhile the NHS coronavirus vaccine booking system was extended for the second time in two days to allow more healthy adults in their 40s to book their jab.

People in England who are aged 42 and over, or those who will turn 42 before July 1, can now arrange their vaccine appointment through the national booking website.

Health Secretary Matt Hancock said he was “standing by” his phone waiting for a text message as he was now eligible for the jab.

He said on Twitter: “I’m really looking forward to getting my text. Yesterday we opened up to people aged 44 – that’s gone very, very well, thank you to the hundreds of thousands who’ve come forward and booked your appointment and now we’re able to go that little bit further.”

Professor Stephen Powis, medical director for the NHS in England, said: “Just two weeks after rolling out the vaccine to those aged 45 and over, we are now ready to invite those aged 42 and 43, as the largest vaccination programme in NHS history continues at speed.

“The rapid rollout of the NHS vaccination programme, the swiftest in Europe, hasn’t happened by accident, it is down to months of careful planning and sheer hard work by nurses, doctors and countless other staff supported by our volunteers.

“If you receive a text inviting you to book in for your jab, please follow the instructions provided, it is simple, effective and provides vital protection against the coronavirus.”

Government data up to April 25 shows that 46,650,008 jabs have been given in the UK so far, including 12,897,123 second doses.

As well as the clinically vulnerable, healthy adults aged 35 and over in Northern Ireland have been invited to book their vaccine appointment.

In Scotland, preparations are ongoing to extend the vaccine rollout to healthy adults in their 40s.

People aged 30 and over are being called for their appointments across most health boards in Wales.

Seven in 10 adults in Wales have had their first Covid-19 jab, including 70% of people in their 40s and 35% of people in their 30s.

Meanwhile, new figures from the Office for National Statistics (ONS) show that a total of 266 deaths occurred in the week ending April 9 where Covid-19 was recorded on the death certificate.

This is down 97% from 8,965 deaths in the week to January 22, the peak of the second wave, when more than a thousand deaths were taking place each day.

A total of 152,205 deaths have now occurred in the UK where Covid-19 was mentioned on the death certificate, the ONS said.

It comes after medical supplies from the UK arrived in India, which is facing a significant wave of infections, with some healthcare facilities in the country buckling under the strain.

The first of nine plane-loads of life-saving kit, including ventilators and oxygen concentrators, arrived in New Delhi early on Tuesday.

The Foreign Office said that the first shipment included 200 ventilators and 95 oxygen concentrators, which will be sent to Indian hospitals.

The move follows discussions with India’s government following a devastating surge in Covid-19 cases which has overwhelmed the country’s health services.

Further consignments are due to be dispatched later this week, including another 400 oxygen concentrators.