Campaign
In general, campaigns rarely make a significant difference to the outcome of elections. There may be a slight widening or tightening in opinion polls but, generally, a party with a clear lead in the polls at the beginning of a campaign tends to win, even if there are occasional mishaps. When polls are tight, however, the campaign can make a difference. On there occasions, one party wins by just a small margin.
However, 2017 broke all political assumptions, showing just how significant a campaign can be. May was 20 points ahead in the polls when she called the election in April 2017. By 8 June, she had lost her parliamentary majority and was seen as an ineffectiveleader and PM
Jeremy Corbyn smashed another widely accepted fact that once the electorate have made their mind up about you, it is impossible to change.He ended the campaign being hailed as the new socialist messiah