While Smiley checks on other former colleagues for details of what is known about the mole, his protégé Peter Guillam plays Burglar Bill by sneaking into the Circus and getting corroboration of Tarr's story and the details of Operation "Testify". Smiley also focuses on source "Merlin", a British spy in the KGB, and his "Witchcraft" material upon which the present heads of the "Circus" owe their positions.
Did You Know?
Although in the series Bill Haydon is ostensibly Toby Esterhaze's senior, in reality actor Bernard Hepton was older than Ian Richardson by ten years, and had in fact directed Richardson in a critically well-received performance of Hamlet in the early 1950's. See more
In the meeting about 20 minutes into the episode, the reflection of the boom mic is visible in the glass in the table at the end in the foreground. See more
You must assume, Peter, the Circus has dogs on you 24 hours a day. Think of it as a foreign country.