The British government will announce the roadmap for a new law on Tuesday prohibiting those entering the country through unofficial routes from seeking asylumin an attempt to stop tens of thousands of immigrants arriving on its shores in small boats.

Prime Minister Rishi Sunak has made a stop to the arrivals of ships one of your five key prioritiese after the number of migrants arriving on the south coast of England soared to more than 45,000 last year, with around 90% of them applying for asylum.

The new legislation will mean that anyone arriving by small boat will not be able to apply for asylum and will be deported to so-called safe third countries, according to government officials, who asked not to be named.

“We have an unacceptable situation, depriving people who really need our help and that’s just not fair, so we have to remove the incentive to jump the line by coming here illegally and stop the boats,” the prime minister’s spokesman said.

The Refugee Council charity said tens of thousands of genuine refugees who previously would have been granted asylum they would be “locked up as criminals” according to the plans, which would “break” Britain’s commitments under the UN refugee convention.

Anger over immigration in some areas has played a defining role in British politics over the past decade, and has been successfully used as a tool by activists to boost support for Brexit ahead of the 2016 referendum.

immigration control was the third most important issue for voters after the economy and the functioning of the health service, a survey conducted by YouGov in November found. The poll found that 87% of the public thought the government was mishandling the issue.