LONDON (AP) — Street artist Banksy has rescinded his offer of a free artwork to voters who oppose the Conservatives in Britain's election, after being warned it breached electoral rules.

The artist had offered prints of a new limited-edition artwork to voters in Conservative-held seats around his hometown of Bristol in southwest England.

On Tuesday he posted a message on his website headed "product recall." It said he had been warned by electoral authorities that the offer "will invalidate the election result. So I regret to announce this ill-conceived and legally dubious promotion has now been cancelled."

Avon and Somerset Police said that it is a criminal offence "for any voter to accept or agree to accept a gift or similar in return for voting or refraining from voting."

Britain's election is Thursday.