Somehow, Jeremy Corbyn and Paul Nuttall have both managed to lose out in the Stoke Central by-election. Labour held onto the seat against the Ukip onslaught, as its candidate Gareth Snell emerged victorious against the embattled Ukip leader Nuttall following a bitter campaign.

But the Labour turnout collapsed against 2015, partly a result of Storm Doris, and also the erosion of support from the party's historic core base among the midlands and northern working classes, a decline compounded by the divisive Brexit issue.

For Ukip, Stoke Central is exactly the type of constituency must-win it needs if it is to establish any meaningful representation in parliament. Nuttall, whose campaign was engulfed in scandal over false claims made about his experience of the Hillsborough disaster, failed to deliver.

It was an even worse story for Corbyn's Labour in Copeland, a former safe seat for the party and one it has held onto for more than 80 years. The Conservative candidate Trudy Harrison triumphed as Storm Doris depressed the turnout and Labour's vote, and the party was hurt by Corbyn's opposition to nuclear power. The Sellafield nuclear power plant is a big local employer.

Following Labour's narrow victory in Stoke and its loss in Copeland, and Ukip's defeat in Stoke, both leaders are tipped to fall before the end of the year. The bookmaker William Hill now has Corbyn at 4/5 to stop being Labour leader in 2017, a 55% chance. Nuttall's odds of ending his Ukip leadership are even shorter at 1/2, a 66% chance.

"It is a moot point whether Corbyn or Nuttall fared worse as a result of the by-elections," said William Hill's spokesman Graham Sharpe. "But the extended leadership of both must now be in considerable doubt."

Ukip's Nuttall is also the favourite to be the next party leader to stand down at 4/6. Corbyn is second at 7/4, Conservative leader Theresa May is third at 9/1. SNP leader Nicola Sturgeon is 10/1 and Lib Dem chief Tim Farron is 12/1 to be next to go.