Britain is imposing visa requirements for all visitors from Dominica, Honduras, Namibia, Timor-Leste and Vanuatu, as Suella Braverman cited abuse of the migration system.

The Home Secretary said the changes were being made “solely for migration and border security reasons” and insisted it is “not a sign of poor relations with these countries”.

In a written statement to MPs on Wednesday, she said Dominica and Vanuatu’s “operation of a citizenship by investment scheme has shown clear and evident abuse”.

The two Commonwealth allies have been granting “citizenship to individuals known to pose a risk to the UK”, she said.

These high numbers are unsustainable, contributing significantly to operational pressures which have resulted in frontline resource being diverted from other operational priorities

Ms Braverman said there had been a “sustained and significant increase” in nationals from Namibia and Honduras who had “abused” their right to visit the UK for a limited period without a visa in order to claim asylum.

“As such, Namibians and Hondurans rank first amongst non-visa nationals for asylum claims,” she wrote.

“These high numbers are unsustainable, contributing significantly to operational pressures which have resulted in frontline resource being diverted from other operational priorities.”

Namibia is another member of the Commonwealth of 56 mainly former British colonies.

As for Timor-Leste, Ms Braverman said there had been a “sustained increase” in its nationals arriving at the border as “non-genuine visitors”.

She said they often had “the intention to fraudulently claim EU Settlement Scheme status as dependants or to work illegally in the UK”.

Ms Braverman was allowing a four-week transition period for those who hold confirmed bookings to the UK to travel without visas before the new regime hits.