That would depend on the residency requirements in Switzerland. If you applied the above to the UK, you would be resident after a time (more than 90 days per year averaged over a four-year period). Other tests may applied such as having a significant centre of interest in the country. It would be clear that he would be living in Switzerland, whether he registered or not (which would also be illegal if he didn't). In any case, it would be to someone's advantage to pay their taxes in Switzerland rather than in the UK if at all possible.

I agree with the other posters - anyone on this thread who has or finds useful information on the topic should post it here - others who find this thread later will thank them.