Animal Aid have exposed the abuse of animals in their before their slaughter. The Guardian has good coverage of the abuse and a rather sickening video. I've seen a lot of 'we must tighten up laws' on twitter around this issue, but the real thing we must do is tighten up our morals. These people should not be compelled in any way to want to do these things, and I'm certain consumers would not want a product with 'we treat animals with great cruelty' stamped on the box.
You can find the animal aid web site here: http://www.animalaid.org.uk