Royal Family's Fab Four Harry, Meghan, William and Kate join the Queen for Westminster Abbey service to mark RAF centenary to watch historic fly-past

Harry, Meghan, William and Kate (pictured left and right) joined the Queen at Westminster Abbey this morning as the royals helped kick off a momentous day-long celebration to mark 100 years of the Royal Air Force (Her Majesty with the Prince of Wales and Duchess of Cornwall, inset). The fab four led a host of dignitaries and politicians, including embattled Prime Minister Theresa May, into the service for the first of several events to take part today, ahead of one of the largest military flypasts in recent memory this afternoon. Up to 100 aircraft from Battle of Britain-era Spitfires and Lancaster Bombers to Britain's cutting-edge F-35 stealth fighter jets will take to the skies from 12.45pm before thundering over Buckingham Palace 15 minutes later. Thousands are expected to line the streets to catch a glimpse of the iconic flypast, while more than a thousand servicemen and women took part in a parade on The Mall.