The Archbishop of Canterbury is urging the government to scrap travel red lists and instead focus on improving vaccine equity for poorer nations.
Justin Welby echoed the criticism of the Nigerian High Commissioner who called the red lists "travel apartheid".
The Archbishop used Twitter to call for Nigeria, South Africa and all other countries currently on the UK's red list to be removed.
In a Twitter thread, he said red lists were "morally wrong" and "self-defeating", and that the only way out of the pandemic was for vaccines to be shared globally.
He called for an end to the stockpiling of vaccines, and for the focus to be shifted to "countries that need them the most".
"We must find fair and effective approaches for those who are vaccinated and tested to enter the UK," he said.
"I agree with the Nigerian High Commissioner to the UK – we cannot have 'travel apartheid'.
"It is also morally wrong – and self-defeating – effectively to punish other nations for being transparent when they discover new Covid variants, as Archbishop Thabo of Cape Town has said.
"The only route out of this pandemic is vaccine equity. We must end vaccine nationalism and stockpiling. We must get vaccines distributed in countries that need them the most. The choice is vaccine nationalism or human solidarity."
The UK's travel red list was reintroduced over concerns about the omicron variant.
Other countries on the red list include Zimbabwe, Malawi and Zambia.
The ban means that only British and Irish residents may enter the UK from these countries.