 From December 1942, German merchant ships which had sought refuge in the territory of Goa in Portuguese India in 1939 began providing regular intelligence on Allied shipping via radio to German U-boats of the Monsun Gruppe operating in the Indian Ocean.Once the British discovered this, the Special Operations Executive launched Operation Creek, using a group of part-time soldiers called the Calcutta Light Horse to infiltrate the harbour and sink the German ship "Ehrenfels" with limpet mines, ending the transmissions.Due to the violation of Portuguese neutrality, the operation was kept secret until 1978.