Philip Knowles, the Lib Dem candidate in Richmond, said the historically safe Tory seat had become more liberal in the last two years and said: “The Conservatives have had it easy round here for way too long.
“On the doorsteps, people are telling us there are sick of their vote being taken for granted and have no time for the type of toxic politics being pushed by Boris Johnson.
“Tactical voting website Best for Britain have run the numbers and are advising people that if you want to take on the Tories in Richmond then you need to vote Lib Dem. Voters are clearly listening.
“Life-long Tories in our area are not just promising us their vote, but proactively tearing up their Tory membership cards and joining the Liberal Democrats.”
But Constituency Agent for the Tories Sam Gibbs said: “If that’s happening, it’s news to me.”
Although he said the membership could “do whatever they want in the comfort of their own living rooms” he said they had in fact seen membership rise as election campaigning took hold.
He said campaigners were “fired up and ready to go” and all those “ho usually help are helping”.
The Tories have held Richmond since 1910 and in the 2010 election had the biggest Conservative majority in the country.
In the 2017 election Cabinet Minister Rishi Sunak had a majority of 23,108.
But Mr Knowles added: “Locally as well as nationally, we have more Lib Dem members than ever before. We beat the Tories and Labour in to fourth and fifth place respectively in the European elections and are feeling confident about this campaign.”
Speaking as the party opened a new constituency headquarters in Trinity Church Square, Mr Knowles said: “Opening the office makes it easier for more people to find out first-hand how we will build a brighter future for our community and sends a clear signal that we mean business.”
The full list of candidates in Richmond is: Thom Kirkwood (Labour), Rishi Sunak (Conservative), Philip Knowles (Liberal Democrat), Laurence Waterhouse (Yorkshire Party), John Yorke (Green Party), and Nick Jardine (Independent).