After months of wrangling between British government lawmakers in the elected House of Commons and the unelected House of Lords, the country's parliament in Westminster has passed the Rwanda bill proposed by Prime Minister Rishi Sunak and sent it to Buckingham Palace for royal assent.

According to the BBC, the saga known as a "parliamentary ping-pong" between MPs and Lords ended just after midnight, London time, after five rounds of negotiations between both houses of parliament and after peers decided not to push their opposition to it any further.

Plans to send some asylum seekers to Africa have long been met with fierce criticism, but the bill passed early into Tuesday morning (Apr. 23) when the Lords dropped their opposition. 

Sunakl said that flights to Rwanda would take off within 10 to 12 weeks, missing its original spring target. However, the plan could still be held up by court challenges. 

Home Secretary James Cleverly said the bill's passing was a "landmark moment in our plan to stop the boats."

"I promised to do what was necessary to clear the path for the first flight. That's what we have done," he said in a video posted on social media. "Now we're working day in and day out to get flights off the ground."

However, Shadow Home Secretary Yvette Cooper said the Rwanda plan was an "extortionately expensive gimmick."

Charities have also criticized the scheme, with leading human rights groups describing it as a "breach of international law."

It could be recalled that the UK's Supreme Court unanimously shut down a similar policy by the Conservative Party last November, finding it unlawful. 

Earlier on Monday (Apr. 22), Sunak said flights were booked to take off as soon as the legislation was passed, and 500 staff were ready to escort migrants "all the way to Rwanda."

"Plans are in place. And these flights will go, come what may," the prime minister said, adding that he wanted to create "a drumbeat of multiple flights a month... because that's how you build a systematic deterrent and that's how you'll stop the boats".

Before it was passed, Sunak had vowed to keep MPs working through the night if necessary to pass his bill and get flights off the ground.