Maybe the people who decide these things don't know much about history - in particular, football history. Back in 1970, Harold Wilson, then the Labour party's Prime Minister, chose to hold a snap general election on 18 June to capitalise on his party's popularity. The result was a foregone conclusion. Labour went into the election with a 12 percentage point lead in the opinion polls.
Then fate intervened. Four days earlier and over 5,000 miles away in Mexico, England's football team, surprisingly - and arguably unfairly - were booted out of the 1970 World Cup tournament when they lost to West Germany. In the national depression that immediately set in - at least in England - voters lashed out at the incumbent Labour government by kicking it out of office.