Spy is insanely funny. Whereas another fantastic spy farce, Archer, is prototypically American (what with the over-the-top gadgetry, lewdness and macho stuff), Spy is equally British (compact, driven by small inflections and absurdities, and politely biting). Spy is rife with the comedic mechanism of interruptive dialogue where characters finish each others sentences or over-speak creating confusion and misdirection -- some intended, some not. It takes careful listening to stay with the dialogue and it's in the subtlety of the delivery that the funniest lines are spoken.
Jude Wright is brilliant as the ber-intelligent and resentful son of the main character, Tim. Tim, portrayed with superb comedic timing by Darren Boyd, is an affably charming man of small wit and large misfortune. And for us, the scenes with Robert Lindsay's zany character, MI-5's examiner, are the gems of the show.
For comedic value, Spy is a 10 to us. Flaws abound in any program, but a rare show like Spy makes one not care. As far as we know Spy is not running for any particular comedic championship. It's just an easy going ride through hilarity.