Special Operations Executive

https://en.wikipedia.org/wiki/Special_Operations_Executive
The Special Operations Executive (SOE) was a British World War II organisation.
Following Cabinet approval, it was officially formed by Minister of Economic Warfare Hugh Dalton on 22 July 1940, to conduct espionage, sabotage and reconnaissance in occupied Europe (and later, in occupied Southeast Asia also) against the Axis powers, and to aid local resistance movements.

MI5

https://en.wikipedia.org/wiki/MI5
From Wikipedia, the free encyclopedia

The Security Service, also MI5 (Military Intelligence, Section 5),[2] is the United Kingdom's domestic counter-intelligence and security agency and is part of its intelligence machinery alongside the Secret Intelligence Service (MI6), Government Communications Headquarters (GCHQ) and Defence Intelligence (DI).
MI5 is directed by the Joint Intelligence Committee (JIC), and the service is bound by the Security Service Act 1989 and the Intelligence Services Act 1994. The service is directed to protect British parliamentary democracy and economic interests, and counter terrorism and espionage within the UK.

Dirty Tricks

By CRaivios, Jul 31, 2009
As with every episode of Foyle's War, there is a true back story. This time, the Special Operations Executive (SOE) was the subject. Its main mission was espionage and sabotage behind enemy lines. In essence, dirty tricks. The SOE operated during WWII, being absorbed into MI6 (the British counterpart to the CIA) after the war.
There were so many threads that seemed not to be related. February 1941. A man parachutes into Northern France. He hides his chute, looks at a map, walks a few feet and is killed when he walks into a mine field.
Foyle's brother in law, who was trying to get Christopher a job in the war effort, was part of a meeting of military personnel. There was a fierce argument between Sir Giles Messinger and Lt. Col James Wintringham about funding, equipment and the need at all for the SOE. A man dealing in contraband was hit in the back of his head and sent to hospital in Hastings. The building across the street from his shop was blown up.
Foyle and his team investigate, only to find a web a deception. It turns out that they are dealing with spies. There are assassination attempts and the revelation a cover up before Foyle pieces together the truth in the end.LESS