The previous British government spent far more than previously announced on a contentious plan to deport asylum seekers to Rwanda, it was announced on Monday.

The policy, which called for sending asylum seekers to the African nation for processing and resettlement, was championed by successive Conservative prime ministers as their flagship plan to tackle irregular migration.

But no asylum seekers were ever deported to Rwanda under the initiative. Four people were put on planes to the central African nation this year, but they were asylum seekers who went voluntarily after being offered £3,000 each.

The policy cost the government some £700 million, or just over $900 million, Britain’s new home secretary, Yvette Cooper, told Parliament on Monday.

“It is the most shocking waste of taxpayers’ money I’ve ever seen,” Ms. Cooper, whose office is responsible for overseeing immigration, told lawmakers.

The previous government, she said, planned to spend more than £10 billion on the plan in total over a six-year period. “They did not tell Parliament that,” Ms. Cooper.

The costs so far have included more than £290 million in direct payments to Rwanda, chartered flights that never took off, the detention and release of hundreds of asylum seekers, and the 1,000 civil servants who worked on the plan.

After the Labour government was elected in a landslide victory earlier this month, Prime Minister Keir Starmer announced that he would scrap the Rwanda plan.

The government said it would look closely at whether any funds could be recovered, but Rwanda was clear that it did not intend to repay the money. A Rwandan government spokesperson said earlier this month that the treaty between the two nations did not include a reimbursement clause and wished the country “good luck.”

The Rwanda policy was first introduced under Boris Johnson’s government in 2022 and was immediately criticized by human rights groups and legal experts who warned it would breach Britain’s obligations under domestic and international law. It was deemed unlawful by Britain’s top court last year.

The Conservative government continued to pursue the policy as a cornerstone of its pledge to stop people from making dangerous crossings by small boats across the English Channel. Rishi Sunak, the last Conservative prime minister, passed a law declaring Rwanda a “safe country” in an attempt to circumvent the Supreme Court ruling and continued to promote the plan ahead of the July 4 general election.

At least 19 people have died while attempting to cross the English Channel in small boats so far in 2024, while more than 15,000 people have made the crossing in small boats, according to government data.

James Cleverly, the Conservative lawmaker who previously served as the home Secretary, claimed the Labour government had “made up numbers” while speaking in Parliament.

In a statement, he said the government “has no credible plan to stop the boats and end the tragic loss of life in the Channel.”

Stephen Castle contributed reporting.