Queen’s birthday: When does she turn 90 and why does she have another 'birthday' in June?

Since the Queen was born, average house prices have risen from £619 in 1926 to just shy of £300,000 today (Getty Images)

Queen Elizabeth II, Britain’s longest ever reigning monarch, will turn 90 on 21 April.

Thursday marks her actual birthday. But the Queen also has a second day celebrating her birth on a Saturday in June.

Why does the Queen have two birthdays?

Traditionally, official celebrations to mark a sovereign’s birthday are held on a day other than their actual birthday - especially if their actual birthday doesn’t fall in summer.

What happens on her birthday?

While the only things most people would be planning for their birthday would be a lie-in and a knees-up down the pub, the Queen’s entire week is structured in such a way that even her activities on the actual day are meticulously planned.

On her actual birthday, the Queen, accompanied by The Duke of Edinburgh, will go on what her officials are calling a “walkabout” of Windsor from the Henry VIII Gate of Windsor Castle towards the Statute of Queen Victoria at the foot of Castle Hill. She will then unveil a plaque to mark The Queen's Walkway, a 6.3km walking trail through the town of Windsor.

In the evening, the pair will light a beacon which will set in train 900 beacons being lit across the world to commemorate her birthday. Her Majesty will no doubt spend much of the day hoping gaffe-prone Prince Philip doesn’t slip-up at some point along the way, what with the increased press attention on the pair.

What happens on her second ‘birthday’?

As her detractors are quick to point out, the Royal family never misses an opportunity for an event marking the monarchy and her second birthday is no exception. This day culminates with the ultimate show: Trooping the Colour, a birthday parade involving red-jacketed soldiers precision marching down towards Horse Guards Parade accompanied by music. The ceremony is watched by the Royal family and the Queen will also inspect 1,100 soldiers of the Household Division. The Queen, Princess William and Kate et al then return to Buckingham Palace to watch an RAF flypast. Nothing too over the top then.