The London Estate, comprising some 6 acres, has been occupied by the HAC since 1641. The property is bounded by Bunhill Fields Burial Ground to the north, Chiswell Street to the south, Bunhill Row to the west and City Road and Finsbury Square to the east The HAC has a ceremonial role which is fulfilled by both the Regiment and Veterans of the Company.

The Regiment provides Guards of Honour for members of the Royal Family and for visiting Heads of State or Commonwealth Prime Ministers. There are normally two State Visits per year and on each occasion the Lord Mayor holds a banquet in the visitor's honour.

When members of the HAC Regiment have completed their term of service with the Territorial Army but wish, in some way, to continue to serve in an organisation of a military character they have the option, provided they remain as members of the Company, to join the Company of Pikemen & Musketeers or the Light Cavalry.

The Company of Pikemen & Musketeers was established in 1925. It received a Royal Warrant 30 years later and this lays down their organisation, numbers and duties. It is an entirely voluntary, unpaid organisation. It is deemed a privilege to be a member and there is a waiting list of members of the Company who wish to join the ranks. The pikemen and musketeers wear the uniform of the period of Charles I and can be seen at State and civic occasions. They serve as the Lord Mayor's bodyguard.

The finest examples of the Company’s extensive collection of uniforms and weapons are displayed in the Museum. The displays include some important shooting medals, reflecting the Company's tradition of excellence in musketry dating from the early 19th century. Service medals are displayed in the Medal Room; the earliest medal sets – all donated by members and their families – date from the Boer War. The VCs won by two members of the Company at Gavrelle in 1917 are proudly displayed in a separate cabinet. The Library, in the Sergeant’s Cottage, contains books relating to the Company’s history, and warfare in the 19th Century and 20th Century