Taking a sneaky shortcut - what law is it breaking?

[johnfm]

Council has recently blocked off a side road along my commute.

I noticed a car taking a shortcut past the bollards and using the side street . Basically there is a dropped kerb going onto a small parking area for some flats and that connects to another parking area also with a dropped kerb.

So, other than trespassing on the flat's car parking, is there a breach of any traffic regs?