The two magnificent west towers, above the Great West Door, were the last major construction work to be carried out on the Abbey, constructed from Portland stone between 1722 and 1745 to a design by Nicholas Hawksmoor. On top of the north tower sits a flag pole on which the Abbey flies flags - of the Commonwealth Nations, the Flag of St Peter, the Abbey Flag, the Union Flag, the Flags of the National Saints, the Royal Air Force Flag, and the Royal Standard.
The Flag of St Peter
Red with a pair of Golden Cross Keys, together with the Ring of St Edward the Confessor. This flag combines the symbols of the two Patron Saints of the Abbey: the ring of St Edward the Confessor, king of England 1043–1066 and founder of the Abbey in 1065; and the keys of St Peter, keeper of the keys to the kingdom of heaven, after whom the Abbey was named when it was re-founded as a Collegiate Church in 1579. It is flown on most Church Festivals, such as the feast of the Blessed Virgin Mary and Christmas Day.
The Abbey Flag
This bears the coat of arms of Westminster Abbey, and is flown during a State Visit on the day when the Head of State visits the Grave of The Unknown Warrior.
The Union Flag is flown on Remembrance Sunday.
The Flags of the National Saints - George, Andrew, and Patrick, are flown on their respective days.
The Welsh Dragon Flag is flown on St David's Day.
The Royal Air Force Flag is flown on the Commemoration of the Battle of Britain.
The Royal Standard is flown whenever the Sovereign is within the Abbey or its Precincts. It is also flown whenever the Sovereign opens Parliament, a privilege granted by King Edward VII.
A Commonwealth National Flag is flown on the day when the High Commission is represented at Evensong.
A small Abbey Flag is flown on all other days not mentioned.