Prime Minister Rishi Sunak's Conservative government wants to send thousands of migrants more than 4,000 miles (6,400 km) away to Rwanda as part of a deal with the central African country agreed last year.

The government sees the plan as central to deterring asylum seekers arriving in small boats from France. Sunak has made this one of his five priorities amid pressure from some of his own Conservative lawmakers and the public to resolve the issue, with his party well behind the main opposition Labour Party in opinion polls ahead of a national election due next year.

In an economic impact assessment published on Monday, the government said the cost of deporting each individual to Rwanda would include an average 105,000-pound payment to Rwanda for hosting each asylum seeker, 22,000 pounds for the flight and escorting, and 18,000 pounds for processing and legal costs.

Home Secretary (interior minister) Suella Braverman said these costs must be considered alongside the impact of deterring others trying to reach Britain and the rising cost of housing asylum seekers.

Unless action is taken, Braverman said that the cost of housing asylum seekers will rise to 11 billion pounds a year, up from about 3.6 billion pounds currently.

"The economic impact assessment clearly shows that doing nothing is not an option," she said.

The government said the potential savings were "highly uncertain", but estimated that to break even the plan would need to have the effect of deterring almost two in five people arriving on small boats.

Labour said the economic assessment was a "complete joke" and it failed to accurately say what the overall cost of the plan would be.

The Scottish National Party accused the government of spending an "astronomical" amount of money deporting desperate people while failing to help people in Britain with the rising costs of mortgages and food bills.

On Thursday, the Court of Appeal will hand down its judgment on whether the Rwanda flights are lawful.

The first planned flight last June was blocked by a last-minute ruling by the European Court of Human Rights, which imposed an injunction preventing any deportations until the conclusion of legal action in Britain.

In December, the High Court in London ruled the policy was lawful, but that decision is being challenged by asylum seekers from countries including Syria, Sudan, Iraq, Iran and Vietnam along with some human rights organisations.

Last year, a record 45,000 people came to Britain in small boats across the Channel, mainly from France. Over 11,000 have arrived so far this year.

($1 = 0.7859 pounds)