HMS BLACKPOOL. This ship happened to be sailing from Chatham to Londonderry just as CDEE Porton Down were in need of a spray-ship. This led to BLACKPOOL being selected to spray a large swathe of the UK with the Biological Warfare simulant Zinc Cadmium sulphide on the night of 7-8 November 1959, as it sailed down the English Channel. A few nights later, HMS BLACKPOOL once again acted as a Porton Down spray-ship, but this time as it sailed up the Irish Sea.