The SOE entanglement by the North Pole game of the Abwehr in Holland was the result of poor discipline on behalf of those controlling agents in the field.The captured agents were consistently indicating that their transmitter was in the hands of the Germans when they transmitted back to their controllers under duress.The game was only exposed when two Dutch agents escaped from capitivity to Switzerland and despite false German propaganda spread about them, were able to convince the British authorities that British SOE intelligence had been compromised. The majority of these agents who were failed by the "system" are remembered on a plaque in Mauthausen.
The "intelligence" supplied to the Military by MI6 had historically been so unreliable that much of the early Ultra material, controlled and supplied by MI6, continued to be treated with suspicion until it gradually gained gained credibility. But the main problem seems to have been MI6s reluctance to pass on valuable intelligence on the grounds of security. MI6 Section V, located at a large house in St Albans called Glenalmond was where Ultra material was sifted, assessed and distributed. It was run by Major Felix Cowgill who suppressed circulation of much of the Ultra output. Another interesting fact is that he was supported by a very able and effective second in command called Harold (Kim) Philby! The relationship between Cowgil and MI5, who were responsible for intelligence related to their network of doublecross agents, became seriously strained due to MI6 deliberately withholding vital intercepts. It took time for the reliabilty of Ultra to appreciated and for MI6 to be pressured to release more material. In some cases the decision was taken to ignored certain intelligence in order to protect the Ultra Secret. Stan
The Belgians captured the German plans for the invasion of the Low Countries and France after a German aircraft crash landed over the border. In the main they were ignored until it was too late. Mechelen Incident - Wikipedia, the free encyclopedia After the 10th May a British Sergeant on a patrol shot up a German staff car and captured further plans. I seem to recall these weren't acted on as effectively as they may have been.
