The three-year-old terrorist from Dorset

Poole Borough Council has just admitted using anti-terror laws to spy on a family. Who were these neighbours from hell, you may ask. Did they stand accused of stockpiling nitroglycerine? Hijacking a superjumbo? Receiving illicit shipments of heroin from Poole Harbour at 4am, and donating the proceeds to Hezbollah?

No. They were suspected of lying about their address, to get their three-year-old daughter into a better school.

Now, this may well be a gross overreaction by one individual local authority, and I'm sure the government will try to write it off as the work of one loony council, rather than a fault with the legislation. But there's an important lesson for our MPs: if you want to vote in greater powers to curtail our civil freedoms, just ask yourselves who else might be using those powers. I'm sure MPs who back 42-day detention assume it'll be used under the watchful eye of Labour. But who has a good enough crystal ball to predict the day when a corrupt or even a malevolent government (as opposed to merely a misguided one) will walk into Downing Street?

This case from Dorset brings home an even more scary lesson - it doesn't even need evil people to be in power for this sort of legislation to be abused. It only takes a handful of well-meaning second-grade local politicians with a major common sense deficit.