The Duke of Cambridge presented the Irish Guards with the traditional St Patrick’s Day shamrock at the Cavalry Barracks in Hounslow.
Prince William handed over baskets of sprigs to the battalion, as well as 150 regimental association members and a number of Army cadets.
The pipes and drums blared out “Ireland’s Call” as the Duke pinned the last shamrock onto the Guard’s mascot, Domhnall, a four-year-old Irish wolfhound.
Those involved in the parade then engaged in a royal salute before they removed their headgear and gave three raucous cheers to mark the occasion.
The regiment’s motto is “Quis Separabit” or “Who shall separate us?”, so it was appropriate that this was the first time in six years that they were all together for the parade.
It was also the inaugural celebration at their new home in west London, having previously been based in Aldershot.
On a glorious day, guests were treated to a stirring rendition of “The Boys of Wexford” as the soldiers took their place in the parade square.
They were followed behind by blocks of retired Irish Guards and squadrons from the regiment’s cadet force.
Cormac Brown, of Farranfore, Co. Kerry, served with the Guards in Britain and Saudi Arabia for 24 years, looking after the officers’ mess for most of his time.
He said: “It’s always nice to come to the parade and, though it seems a long time ago for me, it still brings back memories.”
Commanding Officer Lieutenant Colonel Ian Turner was proud of how the day went, particularly in front of the company’s Royal Colonel and given that it was the first one in Hounslow.
“St Patrick’s Day is a fantastic day to celebrate all things Irish, and today we carried on the great tradition of this fine regiment by having a parade and a party,” he explained.
“And to do so with HRH the Duke of Cambridge just means so much.”
The tradition of the presentation of the shamrock dates back to 1901 when Princess Alexandra offered the clover for the first time.
In the past it has been carried out by the Queen Mother and Princess Anne and, in more recent times, the Duchess of Cambridge.
While it is traditionally undertaken by females, William’s involvement this year was not the first time a male dignitary has stepped forward.
In 1999 Prince Edward presented the shamrock at Oxford Barracks in Munster, Germany, while the duty has twice been performed by the Grand Duke of Luxembourg.