He first appears as one of four members of Hornet Squadron returning to their airfield in a Buick convertible after celebrating 'Pip' Patterson's 21st birthday. Cattermole is carrying a golliwog half as big as himself.
Cattermole quickly proves to be one of the squadron's best pilots. After hearing about a French pilot flying under a nearby bridge, he becomes obsessed with the idea, and pulls the stunt off with aplomb. He is also a bully, picking first on Dicky Starr, and later on Sticky Stickwell. He cajoles Starr into repeating the bridge stunt; Starr succeeds, but by then the water had risen and Starr's Hurricane crashes into the river. He bullies Stickwell incessantly, to the point that Stickwell suffers a nervous breakdown and leaves the squadron.
During the Battle of France and the Battle of Britain, Cattermole becomes the squadron's top ace. His skill and charisma make him popular, even though Pip Patterson calls him "the squadron shit".
He starts bullying a new pilot, Steele-Stebbing. This ends when Steele-Stebbing connects the portable toilet, in which Cattermole was moving his bowels and reading the newspaper, to a tractor and drags it around the airfield. Afterwards the two share a grudging respect. In the climactic dogfight in September 1940 Steele-Stebbing is maimed by a cannonshell, and Cattermole flies alongside him to try to keep him from passing out, and to guide him safely to land. Despite Cattermole's efforts, Steele-Stebbing passes out from loss of blood and collides with the cliffs.
Minutes later, Cattermole's Hurricane is shot up by a Spitfire whose pilot mistook him for a Bf-109. Crippled and helpless, he is then set upon by a formation of Messerschmitts and killed.
First seen sitting on the back of a horse drawn cart during the cross country run.
- September 1939 - :Red Two
- October 1938 - Red Three
- September 1940 (His death) - Yellow Leader
- ↑ Scottish on Mother’s side (Moggy reveals this to Squadron Leader Ramsey on returning from leave in August 1939).
- ↑ Mentions that he is not yet 21 at the start of the novel.
- ↑ Moggy revealed his name to Mary during a visit to her cottage.
- ↑ In the novel, Moggy is killed by a passing Bf-109 at high altitude, shortly after his Hurricane is mistaken for a Bf 109 by a Spitfire pilot, who attacks Moggy while in pursuit of a He 111. In the miniseries his Spitfire is destroyed by a 'Bf-109' which chased Moggy past the airfield at low level.