The UK is on course to “hoard” up to 210m spare coronavirus vaccines by the end of the year, research suggests, as ministers were accused of leaving poorer countries “fighting for scraps”.

Pressure is growing on the government to do more to help nations where tiny proportions of their population have had a first jab given that the UK is opposing a temporary waiver to intellectual property rights for Covid-19 vaccines that would allow more companies abroad to manufacture the doses themselves.

About 467m jabs are on order, with 306m due to be delivered to the UK by the end of 2021, data from life science analytics company Airfinity found. However only about 95m jabs will be needed to fulfil the expected demand of vaccinating all over-16s and giving a booster dose to the most vulnerable in autumn.

Given the average level of take-up for adults who have received a first and second dose stands at just over 80%, if the same level was maintained for those eligible accepting all doses they are offered this year, that would leave a surplus of 210m vaccines. Even if take-up were 100%, the figure would be 186m.

These leftover jabs would help inoculate the about 211 million people living in the world’s 10 least vaccinated countries, said campaign group Global Justice Now, which collated the figures.

Nick Dearden, director of the organisation, told the Guardian it was an “insult to the thousands dying each day” that the UK was offering third doses and preparing to vaccinate teenagers while low- and middle-income countries were left “fighting for scraps”.

He said the issue was compounded by the UK’s efforts to “obstruct” a temporary waiver of intellectual property rights on coronavirus vaccines. The bid was tabled at the World Trade Organization (WTO) in October 2020 by India and South Africa – and has since been backed by countries including the US, France and Italy.

Minutes from the most recent WTO meeting to discuss the proposal concluded that “disagreement persisted on the fundamental question of what is the appropriate and most effective way to address the shortage and inequitable access to vaccines”, with a decision now pushed back until October 2021.

Dearden said the UK was “keeping the global south dependent on donations while hoarding limited vaccine supplies for ourselves” and called it an “obscene injustice”.

The government’s drive to roll out third doses from next month flies in the face of a call by the World Health Organization this week for a moratorium on booster shots in a bid to vaccinate 10% of every country’s population by the end of September. It estimates at least 60-70% of the world needs to be inoculated to reach “global immunity”.

The 10 countries with the smallest proportion of people vaccinated, according to Oxford University’s Our World In Data, are: the Democratic Republic of Congo (0.005%), Haiti (0.003%), Burkina Faso (0.01%), Vanuatu (0.03%), South Sudan (0.04%), Yemen (0.04%), Chad (0.04%), Syria (0.05%), Guinea Bissau (0.06%) and Benin (0.1%).

The situation was akin to “vaccine apartheid”, said Max Lawson, Oxfam’s head of inequality policy. He told the Guardian: “The British government is ignoring the WHO’s advice, issuing booster shots and dogmatically defending vaccine patents. It’s only going to prolong the pandemic, leading to more deaths and, ultimately, to mutations of coronavirus that could undermine the UK’s own vaccination programme.”

Shami Chakrabarti, a former Labour shadow attorney general, said the UK and other wealthy nations “have a responsibility to do all we can to save lives in the global south” but ministers were instead “closing down every avenue for low- and-middle-income countries to access vaccines with sufficient speed and scale”.

“For the government to see such suffering and impede every solution is an utter failure of common decency let alone human rights obligations,” she added.

A government spokesperson said: “The UK is committed to supporting a global recovery to the Covid-19 pandemic and improving access to vaccines.

“We have committed to donate 100m doses by June 2022, with the first deliveries starting last week. On top of this, UK funding is helping to provide more than a billion vaccines to low- and middle-income countries through Covax.”