When were you last in central London or Paris? It's been a long time since Limehouse or Montparnasse were dangerous to walk in at night.
Or for another city center, I go downtown inner harbor/fells point/federal hill Baltimore at night plenty. Most city centers in America are perfectly safe any time of day.
All of these places are in London. They have London postcodes, are inside the M25, and are administered by the Mayor of London.
But I know, it's a broad definition.