RISHI SUNAK’S Rwanda deportation scheme costs could soar to half a billion pounds, plus hundreds of thousands more for each deportee, an investigation by the public spending watchdog found today.

The Home Office has refused to say how much more money, on top of the £290 million already confirmed, Britain has agreed to pay Kigali under the stalled plan.

But a National Audit Office (NAO) report revealed millions more in spending today — including £11,000 for each migrant’s plane ticket.

The total could exceed £490m by 2026.

The government has already sent Rwanda an advance payment of £20m to cover processing and operational costs for the first arrivals.

No asylum-seeker who has arrived in Britain via unauthorised methods has so far been removed to Rwanda under the Tory flagship asylum policy due to legal challenges that resulted in the Supreme Court finding the scheme unlawful.

But the Prime Minister has said he wants flights to start “as soon as practically possible.”

The policy is a key plank of Mr Sunak’s plan to “stop the boats,” as he claims it will be a deterrent to further Channel crossings.

Mr Sunak is trying to revive the policy by passing legislation deeming Rwanda a safe country and ratifying a new treaty with Kigali.

The Rwanda Bill is currently making its way through the House of Lords.

Refugee Council chief executive Enver Solomon said: “These figures reveal the extortionate bill the taxpayer will have to pay the Rwandan government for an unworkable and inhumane scheme that will not deter people seeking protection on our shores.”

And former shadow home secretary Diane Abbott said on social media platform X that the costs are “so astronomical, they are ridiculous.

“They should be billed to the Tory election campaign … because they have nothing to do with a workable or just asylum policy.”

Labour shadow home secretary Yvette Cooper said: “This report reveals the national scandal the Tories have been trying to hide.

“Its shocking analysis shows the costs of the failed Rwanda farce are even higher than previously thought.

“Rishi Sunak has staked his position on this scheme. He must account for this fiasco.”

A Home Office spokesperson said it is “vital” the government responds to “illegal migration with bold, long-term solutions.”