In the last general election UKIP's vote share jumped 18.3% to finish in second place. Former Labour campaigner and now UKIP Stoke branch chairman, Mick Harold, finished 5,179 votes behind the Labour MP.
This is probably the most important by-election for UKIP since Douglas Carswell and Mark Reckless successfully defended their seats after defecting from the Conservatives. A victory in Stoke-on-Trent would be a watershed moment for the party, winning a new seat rather than retaining one held by an incumbent.
In the EU referendum, Stoke-on-Trent voted Leave by a massive 69% and are now losing their Remain-supporting MP. Tribal voting is no less a problem in Stoke as elsewhere in the country but Jeremy Corbyn is driving members and MPs away from the Labour Party.
This one is going to be close.