Not in the London Borough of Tower Hamlets!
Although the Bangladeshi population there is around a third of the total - high but still the minority - the recently-elected mayor and his (inexperienced) cabinet are all Bangladeshis, including the "resources" chief, i.e. the one in control of the huge budget. The ever-watchful Andrew Gilligan has the details, and it really isn't a very good picture that he of necessity paints, especially when one looks at that individual's links to Islamist fundamentalists.
This is a downside of the elected mayor scheme, well-intentioned though it is. It becomes almost too easy for those who are adept at manipulating the electoral system at a local level to take control of a significant area of power, tucked away from the mainstream public eye, especially the national media. If it hadn't been for the Andrew Gilligans, of whom there are far too few, we probably wouldn't be aware of even this much information concerning this single situation.
Of course, whatever systems are in place, there will always be those capable of exploiting them to their own ends and perfectly prepared to do just that. Therefore the elected mayor concept isn't the root cause of the problem and scrapping it wouldn't avoid exploitation of whatever stood in its place. All systems are imperfect.
So, what do we do? I don't have a ready answer; but the first action must be to keep a very close watch on all our elections and those who are elected, especially when they end up with skewed and unrepresentative administrations.