The Irish Guards traditionally receive shamrock from a member of the British royal family on Saint Patrick's Day.
The regiment was formed in 1900 by order of Queen Victoria to commemorate the Irish soldiers who fought in the Second Boer War. Its soldiers are known as the Micks, a traditional nickname for Irish people.
A royal woman, traditionally the regiment's colonel or another senior royal patron, presents shamrock to officers and soldiers during the annual ceremony. The regiment's mascot, an Irish wolfhound, also takes part in the occasion.
The ceremony is a military tradition rather than an official religious requirement of the holiday. The shamrock presentation is therefore distinct from the wider custom of wearing or displaying shamrocks on Saint Patrick's Day.