Reform UK has announced a new pre-election pledge to block migrant detention centers from areas represented by its own MPs or controlled by its own councillors, while prioritizing Green-held areas for new sites.

The party said the policy would be necessary under its plan to deport all illegal migrants from Britain, arguing that tens of thousands of people would have to be detained at any one time before being removed from the country.

Under the proposal, illegal migrants would be held in secure detention centers and would not be allowed to leave while awaiting deportation.

Reform said each migrant would be held for “a couple of weeks” before being removed from Britain.

Today we announce a new policy:

In order to deport all illegal migrants in Britain, Reform will need to detain tens of thousands at a time.

Migrants will not be able to leave these detention centres, and each will be held there a couple of weeks before being deported.

So…

— Reform UK (@reformparty_uk) May 4, 2026

The party then made a direct promise to voters ahead of the council elections, saying a Reform government would not place any migrant detention facility in a constituency represented by a Reform MP. It said the same guarantee would apply to any council area controlled by Reform.

The pledge comes just three days before local elections across much of Britain, in which the right-wing Reform party and left-wing Greens are expected to excel, much to the expense of the governing Labour party.

For all remaining parts of the country, the party said it would prioritize parliamentary constituencies and local authorities controlled by the Greens as locations for detention centers.

“Put simply, if you vote in a Reform council or Reform MP, we guarantee you won’t have a detention center near you,” the party said. “If you vote Green, there’s a good chance you will,” it added.

The party launched a new website to promote the policy, naming it “VoteGreenGetIllegals.com.” It allows users to input the postcode to check the polls ahead of the local elections, and provides a map in which it shows which areas would be targeted for detention centers.

Reform described the policy as an “important exercise in democratic consent,” both for its mass deportation plans and for deciding where detention centers should be located.

This policy is genius. Everyone can get what they vote for – what's not to like?! pic.twitter.com/h293EP9VCY

— Julia Hartley-Brewer (@JuliaHB1) May 4, 2026

The party also singled out Green Party leader Zack Polanski, accusing him of supporting open borders and saying it looked forward to the Greens’ “warm embrace” of the proposal.

The policy marks a sharp escalation in Britain’s immigration debate by tying the location of detention facilities directly to how communities vote.

Reform argues that areas backing its candidates should not be forced to host facilities linked to a policy they support only in principle, while areas represented by parties opposing deportations should not be able to avoid the practical effects of their position.