Hoarding of vaccines by wealthy western nations will result in thousands of needless deaths from Covid-19 in the world’s poorest countries every month unless urgent steps are taken to distribute jabs more fairly, Gordon Brown has said.

In an article for the Guardian, the former Labour prime minister called on the G7 rich industrial nations to hold an emergency summit in order to prevent a billion unused doses being amassed by the end of the year.

Brown, who has repeatedly urged the G7 to share the benefits of vaccine breakthroughs more widely, said the collective failure to turn scientific success into protection for all was a “moral catastrophe”. He added: “If the world were a state, we might well call it a failed one.”

The G7 summit hosted by Boris Johnson in Cornwall in June pledged to make 870m doses available to poor countries through the WHO’s Covax procurement programme, but had so far provided only 100m of them, Brown said.

“Thousands will die this month and for the foreseeable future, not because there are too few vaccines being produced but because they are being hoarded in places that now need them least.”

Vaccine production was already at 1.5bn doses a month and would exceed 2bn a month by the end of the year. “By then, we will have amassed more than 1bn unused vaccines. By mid 2022, that figure could pass 2bn.”

Brown called on the US president, Joe Biden, to convene a special G7 summit on the margins of this month’s United Nations general assembly to agree a plan to transfer the west’s unused supplies to countries in need of them. Releasing 500m doses by the end of September and 200m doses a month thereafter would allow poor countries to immunise 60% of their populations by the middle of next year, he said.

“Until recently, western leaders could defend holding supplies in reserve because they feared interruptions to the manufacturing supply chain. Now there is sufficient capacity to guarantee a rising flow of vaccines for the months ahead. So many doses are being produced that the bigger risk is now that millions may go to waste,” Brown said.

“We have to ask ourselves whether Africa and the rest of the world will ever again trust us if people there continue to lose their lives from lack of vaccination.”