Green’s Dictionary of Slang

(orig. naval) a male homosexual who takes the active role in anal intercourse (however, note cite 1922 in which the narrator claims ‘my old girl’ and 1977, which suggests the opposite).

c.1910		‘Twins’ in Bold (1979) 226: Women they pray for it, / Brown hatters pay for it, / Knob, glorious knob.
1922		H. Champion [song title] Everybody Knows Me in Me Old Brown Hat .
1948		K. Williams Diaries 23 Feb. 23: Made lots of innuendos about actors being hatters and so forth, but I didn’t bite the bait.
1959		J. Yates-Benyon Weak and the Wicked 51: Words such as [...] ‘adrift’ and ‘hatter’ were well-worn synonyms for [...] ‘desertion’, and ‘homosexual’.
1963		C. Wood ‘John Thomas’ Cockade (1965) Act I: You a brown hatter?
1970		G.F. Newman Sir, You Bastard 87: He was reputed to have more brown-hats in high places.
1977		G. Melly Rum, Bum and Concertina (1978) 67: You’re an arse-bandit what acts like ’e was a brown ’atter.
1978		A. Burgess 1985 (1980) 118: ‘Homosexual?’ ‘He might well be for all I know. The bastards he got in with are brown-hatters’.
1980		T. McClenaghan Submariners I i: You dirty little brown hatter.
1984		(con. WW2) T. Jones Heart of Oak [ebook] I was skint, not a bloody penny to my name, and this here hatter— a real toff he was— comes up and pushes the boat out for a few jars.
1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: brown hatter n. One who bowls from the Pavilion end (qv) and in so doing tarnishes his bobbies helmet (qv).
2002		(ref. to 1920s–30s) M. Houlbrook Sun among Cities 219: We treated them as a joke. We had various names for them, not very nice names [...] ‘pansies’ ... ‘brown hatters’.
2012		(con. 1980s) I. Welsh Skagboys 332: Ah take the stricken brown-hatter downstairs and deposit him in the medical room.