Tactical voting: why is it such a big part of British elections?

Voters across the UK will cast their ballots on July 4 to decide who will form the next government. Under the UK’s voting system, known as first past the post, voters choose one candidate standing in their constituency. Whoever wins the most votes out of those candidates becomes a Member of Parliament.

Although it is usually assumed that voters choose the candidate or policies that best reflect their values, this is changing.

According to polling, 19% of voters at this election...