I bought a Metro Stoplock eight years ago. After a year or two, I turned the key in the lock to open it and the key turned without openning the lock. I then had to prise the lock off my steering wheel to be able to drive anywhere.

I got a big screwdriver, and wiggled it around in the hinge, and it took about a minute. If I had a bit more practice, then I'm sure you could get it done in little more time than it takes to remove the thing using the keys. A security device should be more of an inconvenience to a thief than to me!

When I bought a new car, I got a Barrier Deadlock fitted. They drill a hole through the transmission tunnel and fit a lock which locks onto the gear linkage. When you park, you put the car into reverse gear, press a button on the lock and its done. To drive off again, you fit the key, turn it and you're ready.

This is expensive (£220) but very easy to use, with no bits of clutter. You could still tow the car away, but it would take longer to remove the lock than most thieves would be interested in.