Green’s Dictionary of Slang

a simple person; thus Herbert music, music-hall jokes mixed with rock music.

[1902		Ade Breaking Into Society (1904) 178: No wonder that pale-faced Herbert, the would-be High Roller, looked with Awe upon Cousin Jim].
1938		J. Curtis They Drive by Night 13: Good old Pompey. That’s where all the right herbs ended up.
1943		R. Llewellyn None But the Lonely Heart 40: You was waiting for some bright herbert to take a first timer at you. [Ibid.] 95: Case some bright herb comes down here in a bit of a hurry.
1958		‘Hancock’s School’ in Hancock’s Half-Hour (BBC Radio) series 5 4 Mar. Sid James: You’ll have a school of spotty faced herberts in no time.
1963		K. Waterhouse Jubb (1966) 161: Show this Herbert out. He doesn’t want to buy.
1975		‘P.B. Yuill’ Hazell and the Three-card Trick (1977) 52: Think yer too high an’ mighty to drink wiv us common herberts?
1980		(con. 1930s) Barltrop & Wolveridge Muvver Tongue 35: In the early thirties all the herberts went about saying ‘Oh, yeah’, ‘sez you’ and ‘scram’.
1986		F. Taylor Auf Wiedersehen Pet Two 237: Now, what are the other Herberts up to?
1999		Eble Campus Sl. Apr. 4: herb – nerd. Possibly from the proper name Herbert.
2000		J.J. Connolly Layer Cake 254: I’m starting to feel like one of those Herberts who join the army to see the world.
2009		L. McIlvanney All the Colours 279: [A] trio of lurching herberts in Ben Sherman checks.
2015		‘Elvis Costello’ Unfaithful Music 250: [T]he Legs & Co. dance troupe [were] more than able to swat away the attentions of various spotty herberts.