When it seemed as though the Liberal Democrats's candidate for Mayor of London might be Lembit Öpik many flaws with the idea soon became clear. (Is London doomed?) And no, I don't mean the possibility that it could have resulted in the capital being hit by an asteroid. Rather it is the location of Öpik's constituency:
It's still not remotely near Zone 6 is it?
Henley is not so far out (maybe Zone 14 to Montgomeryshire's Zone 100) but is still not in Greater London. And this is one of the reasons why I am deeply uneasy about the idea of Boris Johnson running for Mayor of London. (There are others that I'll go into if/when he declares and the nomination battle is underway - and at the moment it's not entirely clear if Boris is running - see ConservativeHome's London Mayor blog: Boris confirms candidacy on his website... and ten minutes later the confirmation is deleted! - but let's stick to this one for the moment.) It's one thing for a politician to represent the same or overlapping areas on different tiers of authorities - there are many councillors who represent the same area at some or all of county, district, town and parish level, as well as those who sit in the Parliaments and/or Assemblies. But even they run the risk of favouring one "core" area over the rest.
When someone seeks to represent two very different areas then it is hard to avoid questions about whether they are truly committed to either. Or which they will give priority to lobbying for when the two are competing for the same resources. Or if they have strong knowledge and a track record in representing (and in this case administering) the new area. These are points that cannot be made about candidates (or potential candidates) from other parties and then quietly ignored when the same issues arise with a potential candidate from one's own party.
One way for Boris to resolve this would be to resign his seat in Parliament, not upon election for Mayor or even upon securing the Conservative nomination but now (if he is running after all). It would be a gamble certainly. But it would be the surest sign of commitment to the metropolis.