Nope, you can’t do that because the original form has his name on, it officially has personally identifying data and therefore falls under the Data Protection Act, so it has to be properly shredded, not just torn up, and you don’t want to know how many forms you’ll have to fill out before you’re allowed to do that.
(I’m only being slightly sarcastic here, data protection regulations are great for us as individuals, but when you have to deal with it professionally, it’s a pain)