Operation Cauldron - Carella Incident

Carella Incident

In the final test of the series, the Fleetwood-based trawler Carella, with a crew of eighteen, ignored warnings to steer clear and unwittingly sailed through a cloud of plague bacteria (Yersinia pestis) on its return from a fishing trip to the waters around Iceland, causing concern about a possible plague outbreak around its home port in north-west England. The Carella was not stopped for disinfection or medical examination but was kept under covert observation by a destroyer and a fisheries vessel for twenty-one days, and the ship's radio communications were monitored for any kind of medical distress call. The surveillance period included a period of shore-leave at Blackpool, during which the crew mixed with the people of the town as usual. None of the crew became ill.

The incident was dealt with at the highest levels of government, going through the First Sea Lord to the Chancellor of the Exchequer Rab Butler, who was deputising for the absent Winston Churchill. The event was successfully covered up and, after the danger had passed, most of the documents relevant to the case were ordered to be burnt. Even the crew of the Carella were unaware of the incident until approached by a BBC documentary crew more than fifty years later.