LONDON (AP) — A British newspaper says Prince Charles has criticized the government’s plan to start deporting some asylum-seekers to Rwanda, calling it “appalling.”

Citing unnamed sources, the Times newspaper reported late Friday that the heir to the British throne is privately opposed to U.K. Prime Minister Boris Johnson’s policy to send people to the East African country.

A court ruling has paved the way for the first flight under the controversial deal to leave Tuesday with more than 30 people. Britain plans to send some migrants who arrive in the U.K. as stowaways or in small boats to Rwanda, where their asylum claims will be processed. If successful, they will stay in the African country. Human rights groups have called the idea unworkable and inhumane.

The prince’s office neither confirmed nor denied the report.

“We would not comment on supposed anonymous private conversations with the Prince of Wales, except to restate that he remains politically neutral,” Clarence House said in a statement. “Matters of policy are decisions for government.”

The new policy threatens to overshadow the upcoming visit by Charles and his wife Camilla to Rwanda later this month to attend a meeting of Commonwealth leaders.

The Times said a source had heard Charles express opposition to the policy several times in private, and that he was “more than disappointed” by it.

Traditionally, British royals don’t get involved in political matters.

As head of state, Charles’s mother, Queen Elizabeth II, has to remain strictly neutral on political matters and doesn’t vote or stand for election, according to the royal family’s official website.

However, the 73-year-old prince, who is first in line to the throne, has been an outspoken supporter of various causes, such as campaigning against climate change and plastic pollution in oceans. He has also been accused of meddling in politics by speaking up about property developments he opposed and other issues.