Will tactical voting mean defeat for the Conservatives at the next general election?

The good news for Labour and the Liberal Democrats is that the two latest by-elections show voters are doing it by themselves, writes Andrew Grice. But will it become a widespread practice?

The Labour and Liberal Democrat leaders, Sir Keir Starmer and Sir Ed Davey (PA/Getty)

The Conservative Party is suffering another bout of jitters after two crushing by-election defeats in Tiverton and Honiton and Wakefield. The main reason Tory MPs are fretting is that the tactical voting by Labour, Liberal Democrat and Green supporters in both seats makes it hard to dismiss the results as a typical outbreak of midterm blues.

True, parties often bounce back to win a general election after by-election setbacks, when voters have a free hit and know they are not choosing a government. But Thursday’s results have focused Tory minds on the 1997 general election when anti-Tory tactical voting contributed to Tony Blair’s landslide. He and Paddy Ashdown, the Lib Dem leader, became convinced their parties needed to cooperate to end what Roy Jenkins called a century of Tory domination.

They agreed a below-the-radar non-aggression pact in which they soft-pedalled in constituencies where the other party stood a chance of ousting the Tories. Academics calculate that it delivered 30 seats. Although Blair would have won without it, he would not have got the 179 majority that took the Tories 13 years to wipe out.