Ben Houchen and Andy Street are campaigning for Boris Johnson

Incumbents promote messages of support from ex-PM despite otherwise avoiding linking themselves with wider Tory party

Until recently it would have been unthinkable that Labour could unseat Ben Houchen as Tees Valley Mayor. Now polls suggest Labour's Chris McEwan is nipping at his heels. Canvassing in Middlesbrough he told the Mirror how he's concentrating on winning.