The Queen’s Official Birthday. Although the Queen’s real birthday is on the 21st of April, it has been a tradition since 1748 to celebrate the king or queen’s birthday in June. A military parade known as Trooping the Colour is held in London, attended by the Royal Family.Nowadays, St Patrick’s Day is celebrated all over the world, and people of all religions are invited to join in! It’s a festival of Irish culture, with Irish music, dancing, food and drink.