Dominic Raab’s predecessor as Conservative MP for Esher and Walton has told his former constituents to vote Lib Dem and oust the foreign secretary.

Ian Taylor, who held the seat for the Tories for 23 years until passing it on to Raab, said Brexit had “scrambled traditional party allegiances”.

In a statement on Monday morning, he attacked Boris Johnson’s “damaging” decision to leave a no-deal exit on the table with a pledge not to extend the transition period beyond 2020.

Raab has a majority of 23,298 in the Surrey constituency.

But an analysis of YouGov polling data by Datapraxis reported by the Sunday Times suggested voters tactically switching to the Lib Dem candidate Monica Harding could cost him the seat.

Taylor said: “It is not a time for tribal party loyalties.

“The Conservative Party I joined was essentially a broad church, accommodating those of us who stood for one-nation social and economic policies, working closely with our neighbours to create the peaceful and relatively prosperous Europe of recent decades.

“Sadly, I no longer recognise the Conservative Party as it is today.”

He said Johnson’s “Get Brexit Done” slogan was “misleading” as the issue would “dominate and harm British politics for years to come”.

“Esher and Walton residents voted convincingly Remain in the EU referendum,” he said.

“To achieve that objective or even to secure the least harmful Brexit, voting now will need to be tactical rather than by traditional allegiance.

“Monica Harding is, in my personal opinion, the candidate for Esher & Walton best placed to pursue these policies in parliament.”

According to Datapraxis, the prime minister himself is at risk of losing his seat to tactical voting, as is former Conservative leader Iain Duncan Smith and leading Brexiteer Steve Baker.