GHQ Liaison Regiment (known as Phantom) was a special reconnaissance unit of the British Army first formed in 1939 during the early stages of World War II.

[3] In November 1939, Lieut-Col George 'Hoppy' Hopkinson was sent as a military observer to the No 3 British Air Mission and subsequently changed the method of operations to focus upon greater use of wireless communications and mobility to provide assessment from the front line.

Their task was to go around day and night to find all the British, Canadian and American units they could, marking their locations on a map, and passing the information to the main HQ.

This included the famous, desperate, message from Major-General Roy Urquhart that "... unless physical contact is made with us early 25 Sept...consider it unlikely we can hold out long enough ..." Two Phantom officers were subsequently awarded the Military Cross for maintaining these vital communications during the operation.

They were typically equipped with Norton motorcycles, Jeeps, Morris 15cwt trucks and White M3 A1 Scout cars and carried a 107 Receiver, 52 and 22 sets.

Famous Phantom officers included: actors Major David Niven (who initially commanded A Squadron and who remarked in a letter, "these were wonderful days which I would not have missed for anything"), Tam Williams and Willoughby Gray; the MPs Sir Jakie Astor, the Hon.