Green’s Dictionary of Slang

1. involved or caught up in.

1988		A. Payne ‘The Last Video Show’ in Minder [TV script] 44: Tell me about it or I’ll assume you’re webbed up with him.
2000		J.J. Connolly Layer Cake 13: Anyone who get webbed up in the brown get seriously dropped out.

2. having a relationship (with).

2000

J.J. Connolly Layer Cake 56: She’s got webbed up with some geezer in there and that ain’t allowed.