Green’s Dictionary of Slang

(UK society) people like us.

1983		J. Mortimer Rumpole and the Golden Thread 192: ‘They can’t stand him [...] He’s not P.L.U. exactly.’ ‘People Like Us?’ I hazarded a guess.
1997		letter at www.yawningbread.org 2 July 🌐 We are writing to you because all our attempts to get our society ‘People Like Us’ registered have made no headway. PLU is intended as a gay and lesbian support group, to help each other live more positive lives.