Black Rod is best known for his part in the ceremonies surrounding the and the . He summons the Commons to attend the speech and leads them to the Lords. As part of the ritual, as Black Rod approaches the doors to the chamber of the House of Commons to make his summons, they are slammed in his face. This is to symbolize the Commons' independence of the Sovereign. Black Rod then strikes the door three times with his staff, and is then admitted and issues the summons of the monarch to attend.
This ritual is derived from the attempt by to arrest the in 1642, in what was seen as a breach of the constitution. This and prior actions of the King led to the . After that incident, the House of Commons has maintained its right to question the right of the monarch's representative to enter their chamber, although they cannot bar him from entering with lawful authority. In recent years, Black Rod has received jibes on this annual occasion from the outspoken .
Before the of 1800, which united the with the to form the , there was also a Black Rod in the . From 1783 the Irish Black Rod was also Usher of the , so the office continued after the Union. No-one was appointed to the office after the separation of the in 1922.
Black Rod is in theory responsible for carrying the into and out of the chamber for the Speaker of the House of Lords (formerly the , now the ), though this role is delegated to the Usher and Deputy Serjeant-at-Arms, or on judicial occasions, to the Lord Speaker's deputy, the Assistant Serjeant-at-Arms. The mace was introduced in 1876.