Another non-story, perhaps just the Torygraph trying to keep the governments new tough-on-burglars stance, to the fore.
If you deliberately made protective devices to specifically hurt intruders then they might have a case to sue you (I seem to remember walls with glass shards built into the cement tops to deter climbing over!).
The present laws are adequate for the purpose, why do so many people shout "Change the law" at every opportunity? Idiocy!
Can you give some examples (with links) where burglars have successfully sued homeowners over wire mesh? I await with baited breath!!