Clue: City's former special police after fashionable old writer (9)
Answer: INVERNESS
Explanation: Definition: City
A charade of IN ('fashionable') plus VERNE (Jules, 'old writer') plus SS (Schutzstaffel, 'former special police' – the Allgem*e*ine SS had the more police-like duties), with 'after' indicating the order of the particles.