The British government on Thursday announced that it will send migrants who illegally enter through its borders to Rwanda -- in a bid to stop illegal immigration that immediately drew criticism from left-wing politicians and activist groups.

Prime Minister Boris Johnson announced the deal with the East African country, saying that it would allow anyone entering illegally, as well as any illegal immigrant who arrived since Jan 1., to be transported to Rwanda.

BREXIT PASSES FIRST MAJOR TEST IN UKRAINE WAR, OBSERVERS SAY

Johnson said in a speech that the move was made possible by Britain’s departure from the European Union, which gave Britain greater control over its immigration policies.

"This innovative approach driven by our shared humanitarian impulse and made possible by Brexit freedoms, will provide safe and legal routes for asylum while disrupting the business model of the gangs, because it means that economic migrants taking advantage of the asylum system will not get to stay in the U.K.," Johnson said. "While those in genuine need will be properly protected, including with access to legal services, on arrival in Rwanda and given the opportunity to build a new life in that dynamic country supported by the funding we are providing."

Britain migrants

A group of people thought to be migrants are brought in to Dover, Kent, onboard a Border Force vessel following a small boat incident in the Channel, Wednesday, April 13, 2022. Britain's Conservative government has struck a deal with Rwanda to send some asylum-seekers thousands of miles away to the East African country, a move that opposition politicians and refugee groups condemned as inhumane, unworkable and a waste of public money. (Gareth Fuller/PA via AP)

Successive Britain governments have struggled with illegal immigration across the English Channel from France. Migrants will sneak onto the back of trucks or other vehicles coming across the channel between Calais and Dover -- or on small boats across the channel itself, often organized by criminal gangs.

Johnson said that seven out of 10 migrants who arrived on small boats were men under 40. Johnson said that attempted crossers have passed thorough "manifestly safe countries, including many in Europe where they could and should have claimed asylum."

More than 28,000 entered the U.K. on boats in 2021, up from 8,500 in 2020. It has led to concerns about exploitation by gangs, similar to the way cartels have exploited the crisis along the U.S.-Mexico border, and the danger to migrants.

ZELENSKYY CALLS FOR MORE SANCTIONS AS UK'S BORIS JOHNSON MAKES SURPRISE KYIV VISIT

Johnson, in his speech, focused on the costs of illegal immigration to the British taxpayer, claiming the U.K. is generous to immigrants but that "we cannot sustain a parallel illegal system."

"Our compassion may be infinite, but our capacity is not," Johnson said, saying it was unfair to ask British taxpayers to write a "blank check" for anyone who wishes to live in the U.K.

The policy was immediately criticized by human rights groups, who denied Johnson’s assertion that Rwanda is a safe country. It drew criticism from the left-wing Labour Party, with leader Keir Starmer calling the plan "unworkable" and "extortionate" and accused Johnson of seeking to distract from the controversy over his attendance at parties during COVID-19 lockdowns.

The United Nations Refugee Agency (UNHCR) said it had made its objections known to both countries.

"UNHCR remains firmly opposed to arrangements that seek to transfer refugees and asylum seekers to third countries in the absence of sufficient safeguards and standards. Such arrangements simply shift asylum responsibilities, evade international obligations, and are contrary to the letter and spirit of the Refugee Convention," UNHCR Assistant High Commissioner for Protection Gillian Triggs said in a statement.

CLICK HERE TO GET THE FOX NEWS APP

The Rwandan government said the five-year agreement would see Britain paying approximately $157 million for housing and other migrant services. 

Rwandan Foreign Affairs Minister Vincent Biruta said the agreement "is about ensuring that people are protected, respected, and empowered to further their own ambitions and settle permanently in Rwanda if they choose."

The Associated Press contributed to this report.