Prince Charles boards the Underground Tube for the first time in 33 years

Prince Charles joined London Underground commuters as he boarded the Tube for the first time in 33 years.

Bemused passengers looked on as the future King and the Duchess of Cornwall swiped their commemorative Oyster cards at Farringdon Station.

The royal couple took the one-stop journey to King's Cross on the Metropolitan line alongside members of the public.

Prince Charles uses his Oyster card to pass through the barriers

A brand new but empty S-Stock train arrived to transport the royal couple. Having only come into service at Farringdon, passenger numbers were limited.

But throughout the three-minute journey commuters were unable to get close to the royals, who were there to mark the 150 anniversary of the London Underground.

Having arrived in Farringdon by royal limousine, Charles and Camilla were presented with their Oyster cards, each charged with £10.

 But both Charles and Camilla would have been eligible for a Freedom Pass for the over 60s.

While Camilla is thought to have used the London Underground in the past, the prince last travelled on the Tube in 1979 when he opened the first stage of the Jubilee line.

The Duchess of Cornwall is understood to be a fan of Harry Potter, so as she arrived at King's Cross she and the Prince were taken to Platform 9 and ¾.

"Platform 9 ¾" is where the Hogwarts Express departs in the Harry Potter book. The Duchess was also presented with an £8 souvenir photo.

One Australian tourist told Sky News: "The last thing we expected to see in London was the royal family and all of a sudden the doors opened on Platform 9 ¾ and Prince Charles was there."