Are there security clearances higher than Top Secret?

I really need to dig around at home and look in my copies of Big Secrets and Bigger Secrets and re-read this section. Poundstone may have actually written something akin to “more exclusive clearances” rather than “higher clearances”.

Also, IIRC, Poundstone refers to his list of compartmentalized clearances as “in recent use”, which suggests that the clearance names he was passing along were no longer in use even as his books went to press (1983 for Big Secrets, 1986 for Bigger Secrets). “Canoe” could well date back to the late 70s.

The briefing that Reagan received on the 20/11/80 forms the prologue of Woodward’s (somewhat controversial) Veil (Schuster, 1987).

The version in Gerald Kaufman’s How to be a minister (1980; Faber, 1997, p28) is rather idiosyncratically British, but worth quoting: