Disability in the UK is horrendously abused. On my street, I would hazard a guess that 50% of households don't work (on disability or job seekers allowance), 20% are retired, and remaining 30% hold down jobs; ranging from temporary, part-time to full-time. I've known people go on disability because they're 'depressed' (maybe you're depressed because you're stuck at home all day, have no money, and no job satisfaction). Also a favourite here is pretending to have back problems - can't be proven so a lot of people claim this one.
You'll love this one. A guy comes into our office who is on disability for a "bad back" so he can't work. He tells me that he was doing a cash job for a contractor and fell off a ladder and got hurt so now he's suing the contractor and the home owner. Apparently disability still allows someone to make $1,000 a month. So now this useless hunk of humanity will end up scamming the system for even more money. The trouble is that this system is so ingrained in our society that I don't think there is a politician out there who can correct it.