Thieves steal a transformer.

No, not a robot that turns into a car, but a big metal boxy thing that you find in power substations.

http://www.watfordobserver.co.uk/display.var.2314309.0.thieves_cut_power_to_thousands.php

There's just one thing I'd like to know. Why on earth did they steal it? Did they think they could sell it, and if so, who to?

An electric fence?