Hundreds of activists were set to join three by-election battles this weekend in Uxbridge, Mid Bedfordshire and North Yorkshire.
The Conservatives picked local councillor Steve Tuckwell as their candidate for the Uxbridge and South Ruislip by-election triggered by Boris Johnson resigning as the local MP.
He immediately launched an attack on Sadiq Khan’s Ulez extension to London’s suburbs.
Labour’s candidate Danny Beales stressed the ultra low emission zone is not a “binary issue” for local people given air quality issues and also highlighted the cost-of-living crisis.
The Tories won the Uxbridge seat with a majority of 7,210 in 2019.
There is also a by-election in Selby and Ainsty, North Yorkshire, where the Conservative majority was 20,137, after close Johnson ally Nigel Adams quit there.
Ex-Culture Secretary Nadine Dorries, another close ally of Mr Johnson, has said she would resign as MP for Mid-Beds, where the Tories have a majority of 24,664, but is yet to do so.
The Liberal Democrats are targeting Mid-Beds, having overturned a similar majority to win the Tiverton and Honiton by-election from the Tories last year.
Conservative peer and pollster Lord Robert Hayward told The Standard: “All three of these by-elections are in play.
“All parties will treat them as very serious contests.”
