A TUBE journey is the norm for millions of London commuters but for the Prince of Wales and Duchess of Cornwall today was their first joint trip using the Underground.
Charles and Camilla celebrated the 150th anniversary of the capital's transport network by touring a small part of it and visiting some stations.
The Prince and Duchess travelled by Tube riding for a few minutes just one stop from Farringdon to King's Cross on a Metropolitan line train.
Charles last travelled on the Tube network in April 1979 when he opened the first stage of the Jubilee line, while Camilla is thought to have used the London Underground (LU) in the past.
The royal couple were given specially designed oyster cards celebrating the Tube's anniversary and used the pre-paid smart cards to swipe their way through the barriers at Farringdon.
They both qualify for a Freedom Pass for the over-60s, but their oyster cards had £10 credit for the journey, which costs £2.10.
The cards are expected to be retained by the Royal Collection.
In their carriage were senior LU and Transport for London staff and Charles and Camilla sat next to each other on the train bound for Uxbridge in west London, while most of their hosts stood.
The Prince and Duchess travelled along the route of the underground's first line which opened on January 9 1863 and ran services between Paddington and Farringdon.
A brand new train was used for the journey, part of LU's new S-Stock trains, which are being introduced to 40% of the Tube network.
The walk-through, air-conditioned trains are built at the Bombardier facility in Derby, which Charles visited in February last year.
Although the train was empty, members of the public boarded at Farringdon along with the royals but a group of policemen standing further down the carriage meant commuters could not reach the heir to the throne and his wife.
Camilla sat opposite Metropolitan line manager Angela Back and speaking about the immaculate train said: "Very nice, very smart."
"Just one stop?" Charles asked Tube bosses when he and the Duchess arrived at King's Cross station after their three-minute trip from Farringdon.
Prior to boarding, Howard Collins, the Tube's chief operating officer, asked Charles if he would like to drive the train - as he did a year ago during the Bombardier factory visit.
"I will do as I'm told," Charles jokingly replied.
Spotting the media waiting on the same platform, he asked: "Are you all coming on the train?"
He asked Tube managing director Mike Brown whether Transport for London was able to recycle any parts from the old trains.
Mr Brown said this was done as far as possible but there were problems with asbestos.
During the journey, TfL commissioner Sir Peter Hendy told Charles about a steam train that had run on the Tube two weeks ago to mark the anniversary.
"Presumably the whole tunnel gets filled with soot?" Charles asked.
Ms Back said after the journey: "It was a real honour to sit opposite them - I wasn't quite expecting that.
"She (Camilla) was asking me whether or not I had ever been stuck on one of the trains, when you are led out the front (through the tunnel).
"Luckily I have not.
"She also asked whether you could walk from one end of the train to the other.
"I spoke about how the new trains have CCTV and are a lot safer.
"She asked whether or not we can get more people on the trains, which obviously we can."