Poll: One third of voters plan to vote tactically at general election
Such a trend could make it difficult for pollsters to make accurate predictions of the national result after voting finishes on December 12, with UK-wide surveys not picking up seat-by-seat variations.
Scotland has some of the most marginal constituencies in the UK, with North East Fife being defended by the SNP with a majority of just two votes and Perth and North Perthshire with a majority of 21.
The survey by BMG Research for the Electoral Reform Society found that 30 per cent of respondents said they will be “voting for the best-positioned party/candidate to keep out another party/candidate that I dislike”.
Only 51 per cent say they will vote for “the candidate/party I most prefer, regardless of how likely they are to win,” and 19 percent say they don't know - 'a damning indictment of Westminster's anti-choice voting system', according to campaigners.
Pro-EU campaigners have set up numerous websites that claim to advise the public how to cast their vote if they want to stop Brexit — some of which offer contradictory advice - while the Brexit Party pulled out of hundreds of seats, reportedly to avoid 'splitting' the Conservative vote in Tory-held seats.
The ERS, who are calling for a switch from first-past-the-post results to a more proportional system, say the poll findings 'sound alarm bells for our democracy.'
Darren Hughes, ERS chief executive, said: "That one in three feel they have to vote for a 'lesser evil' should sound alarm bells for our democracy. Given the number of contradictory tactical vote recommendations out there this election is looking like a lottery under Westminster's broken voting system - one where we all lose.
"It's time for a voting system where you don't have to second guess other voters but where seats match votes and these invidious decisions become a thing of the past. Voters want real choice and a strong voice - and the ability to vote with their hearts. That isn't such a radical idea.
"Let's move our democracy into the 21st century and make this the last election under Westminster's 'hold your nose' electoral system."