Pinner was once described as 'the most boring place in the world' by some actress (Gemma Arterton??). Proper suburbia. fast train (met line) into London for all the accountants and alike. Mostly white/Hindu. Never any trouble including the surrounding districts of Ruislip, Eastcote, Hatch End. Needless to say, house prices are insane.
Problem is it neighbours Harrow which just resembles some Star Wars cafe of 250,000 people. White flight has taken hold big time, celebrated as diversity - Somali, Eritraen, Poles, Roma, Sri-lankan, Syrian etc... anything but anglos (especially under 50). They've all gone to Pinner/Eastcote/Ruislip if they can afford it - except for a handful of druggie losers who are housed in grim Ruislip Manor.
Result - new turf wars. Though I doubt they're supplying the middle class of Pinner as Cressida Dicksplash insists.