Catalogue description Committee of Imperial Defence: Home Ports Defence Committee later Home Defence Committee: Memoranda and Sub-Committees Papers (HPDC, HDC, and ADGB Series)

Loosely chronological by HPDC and HDC reference, and then by sub-committee. The original numerical sequence of the creating bodies has been followed.

The Home Ports Defence Committee (HPDC) was a principal standing committee of the Committee of Imperial Defence. The HPDC was appointed in 1909 to deal with the armament of coast defences and home ports. Its membership included representatives of the CID and additional representatives of the Admiralty, War Office and Air Ministry. In December 1922, the Committee's remit was extended to include all aspects of Home Defence and its title amended to Home Defence Committee (HDC).

Sub-committees were appointed by the HPDC and HDC as necessary to deal with the Protection of Cable Landings, the Protection of Government Offices, the Protection of Posts and Telegraphs, the Protection of Oil and Petrol Stores, Air Defence, the Protection of Vulnerable Points, and the Co-ordination of Active and Passive Air Attacks. All sub-committees had the power to co-opt individuals from the services and other government departments as required.

The memoranda of the HPDC, HDC and of their sub-committees were circulated by the Secretary to members of the committees, to other members of the CID, to ministers, and to other officers and officials who needed to be kept informed of decisions of the committees.