Alan Whickers, n. — Green’s Dictionary of Slang

Alan Whickers n.

also alans

[rhy. sl.; ult. Alan Whicker, UK journalist and TV personality (b.1925)]

knickers.

1971		Daily Tel. 17 Sept. n.p.: Alan Whickers = ‘knickers’.
1984		(ref. to 1965) Partridge DSUE (8th edn) 10/2: Alan Whickers; short form Alans. [...] not before 1965.
2001		G. Coughlan Everyday Eng. and Sl. 🌐 Alans or Alan Wickers [sic] (n): nickers [sic]; as in keep your alans on; calm down.
2002		Guardian 28 Feb. 21: Awright, awright. Keep yer Alans on.
2011		Times Mag. 30 Apr. 14/1: Maybe you call them undies, knickers, briefs, gruds, Alan Whickers?