I don't know what it's like in the UK, but in the US, as a practical matter, the law says whatever a lawyer can convince a judge it says. Many lawyers hate the idea but over the years it works out that way. It's called case law and precedent and it's sometimes been the source of very odd decisions; ie. a burgler falling through a rotten skylight on a museum roof and successfully sueing for failure to maintain safe premises. The main topic here is a similar case, so I won't be suprised if the plaintiffs prevail.