Get a TV for Christmas? Don't Forget a Licence

If you have a television set in the UK, you are required to have a licence for it. The licensing police are out looking for people who acquired new televisions for Christmas but "neglected" to obtain a licence at the same time. And the licence police are very sophisticated [links via JC]:

“Our database of over 28 million addresses shows us all unlicensed properties. Together with our fleet of hi-tech detector vans, this means we are more efficient than Santa himself when it comes to knowing who deserves a Christmas visit.”

Here, buried among many comments, is how it works:

The detector listens for EM transmissions typical of a TV. Every piece of electrical gear gives off some EM waves. TVs have their own unique EM signature and that's what they look for. They're absolutely not a myth. They have a database of all the people who've got a license. They then cruise the streets slowly, looking for EM signatures. When they find one, they check the database and if the house in question has no license, they knock on the door and you're turned into a criminal.