Brain scans could be more accurate than opinion polls at predicting voting intention, researchers at Kingston University have claimed.

While studying brain activity of voters in the five weeks up to the EU referendum, the researchers examined patterns of brain activity in a group of pro-remain and pro-leave voters.

The group also included those who said they were undecided.

Using an electroencephalogram (EEG), they tracked a brainwave called N400 which is triggered when a person reads or hears a statement that goes against their personal, social or political beliefs.

Each participant was shown a series of politically charged statements which supported remain or leave views – such as “If Britain leaves Europe our quality of life will be enhanced” – and their brain activity was monitored.

Dr Giulia Galli, senior lecturer in psychology at Kingston University, who led the study alongside academics from the University of Essex, found the responses were “surprisingly accurate”.

She said: “We wanted to see if the pattern of brain activity would reflect people's social beliefs - and the results not only showed this, but were able to accurately forecast the way each participant went on to vote in the EU referendum.”

When it came to undecided voters, it seems they were less on the fence than they admitted or knew.

The findings showed that not only did brain activity in this group show they had clear social and political preferences, scans taken in the weeks leading up to the poll also correctly predicted how they then voted in the EU referendum.

Dr Galli said this raises the question of whether we all hold inherent beliefs and opinions that we are not entirely conscious of.

She said: “Assuming that our participants didn't lie to us and were actually undecided about which way they were going to vote, we believe that they did have a preference for remain or leave and were not fully aware of this.

“Another reason could be that they had some ideas or opinions but hadn't fully decided on how to vote.”

However, Dr Galli thinks it is unlikely brain scanning will be used to predict voters’ intentions in the future.

She said: “The accuracy of brain activity in predicting voting behaviour is an important finding – particularly when you consider the impact that undecided voters had on the result of the EU referendum.

“However, EEG is very time-consuming, so I think it's improbable that it could be used in practice by politicians to scan the brains of individuals to predict results.”