Rishi Sunak was not entirely convinced about sending illegal migrants to Rwanda while their asylum claims were assessed during his time as chancellor, a UK media report claimed on Saturday.

The 43-year-old British Indian leader, who has been championing the scheme as Prime Minister, had significant doubts over the policy when he was finance minister in former boss Boris Johnson’s Cabinet, the BBC report says based on papers it has seen from two years ago.

The documents suggest Sunak was concerned about the cost of sending asylum seekers to the East African country and wanted to limit the numbers initially.

A source close to Sunak told the BBC: "The Prime Minister was always fully behind the principle of the scheme as a deterrent.

"As chancellor, it was his job to make sure it delivered and taxpayers' money was appropriately spent." Sunak, who took charge at 10 Downing Street in October 2022, was the UK's Chancellor of the Exchequer in No. 11 Downing Street when the Rwanda policy was first announced in April 2022. The deal with Rwanda has since been caught up in legal challenges and no asylum seekers have been sent from the UK so far.

However, Sunak has stressed that the scheme is a key pillar of his strategy to tackle illegal migration to the UK and will also act as a deterrent to the thousands landing on the country’s shores after making treacherous journeys in small boats across the English Channel.

Now, the BBC’s revelations indicate he was not entirely behind the scheme when it was first mooted. The No. 10 documents were prepared in March 2022 as former prime minister Boris Johnson was trying to persuade Sunak – his chancellor – to sign off on more funding for the plan, the report claims.

This was shortly before the agreement with the Rwandan government to process migrants in the African country was signed.

“They suggest Mr Sunak was concerned about the cost of sending asylum seekers to the African country, and wanted to limit the numbers initially. They say, the ‘chancellor wants to pursue smaller volumes initially, 500 instead of 1,500’ in the first year, and ‘3,000 instead of 5,000 in years two and three’,” according to the BBC report.

“The documents describe a significant difference of view between No. 10 and 11 Downing Street on the effectiveness of the proposed scheme saying the chancellor believes the ‘deterrent won't work’,” it adds.

The controversial Safety of Rwanda Bill is now going through its parliamentary process after it cleared the first hurdle in the House of Commons last month.

However, with around 38 MPs of Sunak's own Conservative Party recorded as not taking part in the vote, it is widely expected that the issue will reignite the deep Tory divisions over the policy as it progresses through further stages in the coming weeks.

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