Bradley has been appointed as Reform UK’s "head of local government action", with a focus on reducing council spending.
He stated that trust in the Conservative Party "has gone" and Reform is the only party prepared to tackle pressing issues.
Reform leader Nigel Farage defended welcoming former Conservatives, arguing the party needs experienced people but will not become "Conservative Party 2.0".
Labour criticised the defections, with Treasury minister Torsten Bell suggesting Reform is a "rebranding of the nutty fringe of the Conservative Party".