Britain has signed a new treaty with Rwanda which it said would overcome a court decision blocking its plan to deport asylum seekers to the East African country, a ruling that dealt a huge blow to the government's immigration policy.

The Rwanda scheme aims to stop illegal migration and is being watched closely by other countries considering similar policies.

But in November, the United Kingdom's Supreme Court ruled that the plan would violate international human rights laws enshrined in domestic legislation.

Under the new treaty, signed by British Home Secretary (interior minister) James Cleverly and which replaces a non-binding memorandum of understanding, Britain said Rwanda would not expel asylum seekers to a country where their life or freedom would be threatened - one of the court's major concerns.

There will also be a monitoring committee to enable individuals to lodge confidential complaints directly to them, and a new appeal body made up of judges from around the world.

Cleverly said he expected migrants to be heading to Rwanda in the coming months because the treaty addressed all the issues raised by the Supreme Court

"I really hope that we can now move quickly," Cleverly told reporters in Rwanda's capital Kigali.

Under the plan agreed last year, Britain intends to send thousands of asylum seekers who arrived on its shores without permission to Rwanda to deter migrants making the dangerous journey across the Channel from Europe in small boats.

In return, Rwanda has received an initial payment of 140 million pounds ($180 million) with the promise of more money to fund the accommodation and care of any deported individuals.

However, many lawyers and charities said it was unlikely that deportation flights could start before an election expected next year. The opposition Labour Party, which has a double-digit lead in the polls, plans to ditch the Rwanda policy if it wins.

UK Prime Minister Rishi Sunak, now in power for just over a year, is under intense pressure from both his own lawmakers and many voters to cut net migration, which hit a record 745,000 last year, with the vast majority coming through legal routes.