Boris Johnson reaches 100th day as prime minister

Boris Johnson clocks up the 100th day of his premiership on Thursday – the same day that the UK was originally due to leave the European Union.

But he still has a few weeks to go until he avoids the dubious honour of being the UK’s shortest-serving prime minister.

Mr Johnson will pass that milestone on November 19, when the general election campaign is due to be in full swing.

On that date he will overtake George Canning, who managed 118 days as prime minister before his death in 1827, and who currently holds the record for the shortest time in office.

He will overtake another of his Tory predecessors on December 1: the 1st Viscount Goderich, who served as PM for 130 days in 1827-28.

Were the Conservatives to lose the general election on December 12, Mr Johnson would, therefore, end up as the prime minister with the third shortest time in office.

Mr Johnson is not the first PM in recent decades to find himself heading to the polls soon after entering Downing Street.

Anthony Eden became prime minister on April 6 1955 and called an election almost immediately, seeking to increase the Conservative Party’s majority in the House of Commons.

Mr Eden won the election but ended up one of the shortest-serving PMs of the 20th century, managing just 644 days in office before resigning in the wake of the Suez Crisis on grounds of ill health.