The UK government is planning to deport thousands of asylum seekers per month from next year, a person familiar said, as Prime Minister Rishi Sunak comes under rising pressure over his failure to reduce migration.

Beginning in January the Home Office aims to be able to detain and deport every month more than 3,000 people who it says have traveled to the country illegally, according to the person, who requested anonymity discussing unannounced proposals. The figure was first reported by the Guardian.

The plan is designed to help deliver on Sunak’s promise to “stop the boats,” one of five core pledges he’s asked voters to judge him on. It’s also intended to clear the backlog in processing asylum seekers, which Home Office figures show reached a record high of 172,758 people who had not yet received a decision on their claim by the end of March.

The new ambition for deportations comes as the government faces criticism from both Conservative Members of Parliament and the opposition Labour Party over its broken manifesto commitment to reduce overall net migration — a figure tallying only those deemed to have entered the country legally.

Net migration to the UK was a record 606,000 in 2022, the Office for National Statistics said this week. That’s a long way above the “tens of thousands” that the ruling Conservatives pledged through most of the 2010s to get it down to, and more than double the level at the time of the 2019 general election when the Tories dropped that promise in favor of one simply stating “overall numbers will come down.” Sunak has prioritized tackling unscheduled arrivals by boat, rather than those obtaining visas.