China and Barbados’ relations have strengthened in recent years with the island joining Beijing’s Chinese Belt and Road initiative in 2019. Under the initiative, China lends money to poorer countries to help them fund infrastructure projects including ports and high speed rail lines.
China is able to seize control of the finished projects if the country defaults.
Mr Johnson said China needs to be more “transparent” about its financial dealings with other countries.
Barbados gained independence in 1966 and recently announced that it would become a republic in 2021.
The island’s Governor-General Dame Sandra Mason said “the time has come to fully leave our colonial past behind.”
She added: “Barbadians want a Barbadian Head of State.”
US intelligence which was shared with the UK suggests that pressure was placed on Barbados by China to end the colonial ties with Britain.
Tom Tugendhat, Conservative chairman of the Foreign Affairs Committee, said the evidence indicates that Beijing is “tying new nations into their own imperial order” by using “debt diplomacy”.
He wrote in the Mail on Sunday: “Barbados may be the latest trophy in Beijing’s imperial string of pearls.
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In 2017, former prime minister, David Cameron announced he was helping to create a $1 billion “UK-China Fund”.
He said the fund would be used “to seek opportunities for co-operation between the two countries in technology”.
A Downing Street source told the Daily Mail: “As coronavirus devastates developing countries, many are finding themselves in a Chinese chokehold as a result of the huge debts they owe.
“The Belt and Road Initiative is an expansionist Chinese Marshall Plan – for instance Beijing is funding a high speed rail line in Laos which is costing the equivalent of more than a quarter of the country’s GDP.
“China is doing this in the least transparent way – providing high-interest and unsustainable loans collateralised against countries’ natural resources.
“They are in danger of being forced to sell out future generations to meet their present debts.”
The source said China needs to be more transparent with its affairs.
They said: “As a member of both the UN Security Council and G20, China needs to step up to its obligations and end its chronic lack of transparency.”
Charlie Robertson, an expert on Chinese debt diplomacy, told the Daily Mail: “China is doing what Britain did in the Victorian era – exporting its savings to other countries as an exercise in global domination.
“It has inevitably led to conspiracy theories about China hoping that the countries will default so they can seize critical infrastructure.”