02/06/2017 10:53 BST | Updated 02/06/2017 10:57 BST

Tactical Voting At 2017 General Election Is Now Planned By One Fifth Of Voters

Could be used by one fifth of voters.

One in five voters are planning to use their ballot tactically in the General Election next week, a study has shown as polls suggest the gap between Tories and Labour has narrowed. 

Ukip voters, according to the Electoral Reform Society, are most likely to use the tactic which sees them use their vote to prevent an undesirable outcome, rather than to back their preferred candidate.

Darren Hughes, ERS deputy chief executive, was quoted in the Financial Times on Friday as saying the number of people who feel unable to vote for their first choice party was “astonishing”.

The rise in tactical voting intentions, he said, was “significant and worrying”.

CHRIS J RATCLIFFE via Getty Images
A new study has shown that 20% of Britons plan to use tactical voting in the 2017 General Election and Ukip supporters are most likely to employ the tactic 

Of those polled by BMG Research on behalf of the ERS, 20% said they will vote tactically, and a third of those supporting Ukip said they would employ the tactic.

A further finding is that tactical voters tended to be concentrated in certain parts of the country. Numbers peaked, at a quarter, in the north-east and the east Midlands. 

Of the remaining voters surveyed, just under 60% said they would definitely vote for their preferred candidate. A further 22% were still undecided. 

Hughes said that tactical voting had become more popular due to Britain’s “arcane voting system” which sees voters feeling compelled to vote for their second or even third-choice party - or trying to second-guess how others will vote at the ballot box. 

“This whole situation turns elections into a gamble around splitting the vote and trying to predict who on the left/right is most likely to win,” he said. 

Tactical voting is now so entrenched in the UK political landscape that websites matching voters from different constituencies - who want to swap votes for maximum effect - have proliferated in recent years. 

The ERS wants the UK to introduce proportional representation for Westminster elections, with voters ranking candidates by preference.