The terrible scenes in India – where people are dying in hospital corridors and bodies are being cremated in car parks – have led the government to step up its emergency aid to Delhi.
“The UK will always be there for India in its time of need,” Mr Johnson said, announcing the boost to the 200 ventilators, 495 oxygen concentrators and 3 oxygen generation units already being sent.
In addition, the UK’s health and science chiefs – Professor Chris Whitty and Sir Patrick Vallance – are giving advice to their Indian counterparts on coping with the worst pandemic surge the world has so far seen.
But pressure is growing on the prime minister to scrap or shelve an agreement to receive the 5 million doses, the delivery of which has already been delayed by the Delhi government because of the crisis.
Professor Andrew Pollard, who runs the Oxford Vaccine Group, said it was unacceptable for the UK to be vaccinating younger age groups with “thousands of people dying” in poorer nations.
And he was backed by the leading immunologist and government adviser Peter Openshaw, who agreed the UK should not “take the vaccines away while this situation is so serious”.
“That would seem a very reasonable arrangement to come to,” Prof Openshaw said, adding: “We in this country ordered at least twice as much vaccine as we could possibly use.”
Prof Openshaw, a member of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said the UK could donate about 120 million doses to struggling countries.
But he told the BBC’s Andrew Marr Show that it was best to work through the World Health Organisation (WHO) rather than giving vaccines directly to specific countries.
“That doesn’t mean we have actually got it in store houses ready to go out, but certainly we could be donating something over 120 million doses, but probably best through the WHO Covax system,” he said.
But, when asked about giving vaccines to India, the foreign secretary Dominic Raab said: “I haven’t had a request I can tell you on that specifically.”
His Labour shadow, Lisa Nandy, also backed the UK completing its vaccination programme first, saying: “We haven’t defeated this virus in Britain yet and we need to keep up the momentum.”
But Patrick Watt, Christian Aid’s director of policy, said: “Now that almost all British adults in high-risk categories have been vaccinated – many of them with doses made in India – the UK should be sharing supplies with South Asia and other poorer regions where rollout has been slow.”
On Tuesday, Mr Johnson will hold a virtual meeting with Narendra Modi, the Indian prime minister, “to deepen cooperation”, having been forced to scrap a planned visit last month.