Warnings have been issued for foreign visitors to the UK.
The vast majority must now obtain electronic travel authorization in advance.
Incoming travelers who did not comply were previously given a pass, but this option will end in February 2026.
Visitors from 85 nationalities, including the US, Canada and France, who do not require a visa cannot legally enter the UK without an ETA.
The Home Office said this was a significant step towards digitizing the immigration system and paving the way for a contactless UK border in the future.
Mike Tapp, the Minister for Migration and Citizenship, said: “While the ETA was introduced, it was not strictly enforced to give visitors sufficient time to adapt to the new requirements.
Passengers in Gatwick (PA)
“This is the same approach that other countries such as the United States and Canada took to their travel plans.”
Airlines would screen passengers before travel, the government added.
Since ETA launched in October 2023, more than 13.3 million visitors have successfully applied and benefited from a faster and smoother journey, the Interior Ministry said.
The system is now an essential part of holiday and business travel, including for foreign visitors who need to take connecting flights and go through passport control in the UK.
A spokesperson added: “Anyone wishing to travel to the UK – with the exception of British and Irish citizens – requires travel authorization before entering the country. This can be done either through an Electronic Travel Authorization or an e-Visa.”
Following pressure from London Heathrow Airport, ministers have scrapped the bizarre requirement for passengers to obtain an ETA for just a few hours “airside”.