well i just took my first wheel clamp off (im sure its legal if you dont damage it) they were using a very large armoured padlock.
took about five mins to pick it has had to push the bar in hard and use a lot of tension, raking seemed the easy option,
dam wardens
Beware its only legal to remove them on private land if put on by private clampers. A new law was passed prohibiting the removal of a clamp put on by traffic wardens and the like.
If something happens to the clamp after you left it the person who was clamped will liable for it. They really need to hand it in to a police station and tell the clamping company thats where it is. Ive posted a thread in the faq section on the law on this.