Translation please

Posted by Lotg on September 17, 2004

I've finished my Mark Billingham book, but there are still a few phrases that had me tricked.

The scene is 3 coppers waiting in a meeting room for a meeting to begin. But there was still someone due to arrive. "Where's that plum from SO7 anyway?" asked Stone. "He's never here when he's needed is he?"

What does 'plum' mean in this context? I really couldn't figure it out. Didn't know if it inferred snobbery, uselessness, the reverse, a bootlicker? No idea. Any help please?