MPX5138953: Pickets, members of the Union of Post Office Workers and Postal and Telegraph officers were on duty outside the Overseas Telephone Exchange, Wren House, Carter Lane, London. But despite this, many telephonists reported for duty. Police officers move in to assist bread deliveries into Wren House, as pickets attempt to talk them out of their delivery to the staff canteen. 20th January 1971 (b/w photo) / Bridgeman Images