Elecric shock collars are cruel and should not be used in traiming any animal. The phycological damage an elecric shock collar causes to a dog is horrendous. 

Shock collars used to be a good way or an easy way of training your dog not to run off. However, studies have now shown that positive reinforcement techniques are far better for your dog. 

An elecric collar sends an elecric shock through your dogs body with the push of a button. Not only does this inflict pain on the animal it also causes phycological damage. Dogs have a threshold of pain and elecric collars as well as abusive behaviour has shown that it can cause aggressive behaviours in dogs. 

They have been banned in Wales and it' about time it's bought in to the rest of the UK.