It depends whether or not he 'deserves' it. If he attended Oxbridge, then I will see it as more acceptable. If he went to London met I would think he is getting far too ahead of himself, he doesn't deserve to learn in style, he should just wear his Nike tracksuit with his JustDoIt bag as it fits the image of London met.
I think people should dress reasonably smartly for uni. They're adults.
However, what is normal is judged by the majority culture. In the case of university dress codes, this is people wearing jeans and a t-shirt. Although you do get various kinds of people wearing all sorts of things at uni and perhaps at most prestigious unis some students do wear suits. So a suit would be a bit different, but not so completely abnormal that others think you're mad.
There's a guy in one of my lectures that always wears flared trousers, a shirt, waistcoat, tie, pocket watch and a trilby, and he has long hair. He can pull it off but he must be in his late thirties and has gone more for a Victorian gentleman/hippy look. It would definitely depend if the guy had enough confidence to work it, although I would find a tophat and briefcase a bit of an overkill.