Portcullises fortified the entrances to many medievalcastles, securely closing off the castle during time of attack or siege. Each portcullis was mounted in vertical grooves in castle walls and could be raised or lowered quickly by means of chains or ropes attached to an internal winch.
There would often be two portcullises to the main entrance. The one closer to the inside would be closed first and then the one farther away. This was used to trap the enemy and often, burning wood or fire-heated sand would be dropped onto them from the roof or murder-holes. Hot oil, however, was not commonly used in this manner, contrary to popular belief, since oil was extremely expensive. There were often arrowslits in the sides of the walls, enabling archers and crossbowmen to eliminate the trapped group of attackers.
It is through Lord Charles Somerset, son of the 5th Duke of Beaufort, that the portcullis has found its way into several South African coats of arms. Somerset established several towns during his governorship at the then Cape Colony and named them for his family. These include Worcester, Somerset West, Fort Beaufort and Beaufort West. Institutions that derive the portcullis from these arms include a school, chamber of commerce and a rugby club. Other (approximately 30) South African coats of arms that include a portcullis are not necessarily related to either Lord Somerset or any of the town named for and by him.
Although the Palace of Westminster served as the official royal residence for both Henry VII and Henry VIII until 1530, the current use of the portcullis as a symbol of the Palace and of Parliament does not date from that time. Rather, the symbol was developed as part of Sir Charles Barry's plans for the rebuilt Palace after the original burned down on 16 October 1834; he conceptualized the new Palace as a "legislative castle", and the symbol of a castle gate—i.e. a portcullis—fitted well with the scheme.
Since then, the portcullis has become the primary symbol of Parliament; an office building for Members of Parliament, opened in 2001, is named "Portcullis House". During the 20th century, use of the portcullis as a symbol of Parliament spread beyond Britain and to the other Commonwealth realms; for instance, the coat of arms of Canberra features a portcullis in its crest, consciously preserving a connection between the British Parliament at Westminster and the Australian Parliament to which Canberra is home.
as a charge in its own right, as in the arms of the London Borough of Richmond: Ermine, a portcullis chained or, a bordure gules charged with eight fleurs-de-lys or
with nail heads shown in a contrasting colour, as in the arms of Wallingford Town Council: Gules, a portcullis or studded sable, chained Argent, ensigned with an ancient crown of the second, all within an orle of bezants
with spikes of a contrasting colour, as in the crest of Tendring District Council: ...a portcullis or, nailed and spiked azure
in the gateways of castles, fully lowered or part raised, as in the arms of Winchester City Council: ...five castles triple towered in saltire argent masoned proper the portcullis of each part-raised or...; though these do not appear in gateways of castles unless the blazon specifies them.
It is often shown with chains attached, even when the blazon does not mention them.