Former Conservative MP Dame Andrea Jenkyns has joined Reform UK and will stand as the party's candidate to be Mayor of Greater Lincolnshire in May 2025.
Dame Andrea, who lost her seat in the July general election, said she had "fought to the bitter end" but the Conservative Party was now "beyond salvage".
She said Reform UK were "patriotic bravehearts" who would "deliver the fresh start this country so desperately needs".
It came as the Reform UK's leader Nigel Farage said his party's membership had exceeded 100,000.