Greater London -Perivale
Queueing traffic on exit slip road on A40 Western Avenue Eastbound at A406 North Circular Road (Hanger Lane Gyratory).
Due to a serious accident on the North Circular,just north of the Hanger Lane Gyratory.
More top news
It is the fourth time in five years that the London borough has topped the rankings, according to data from the ONS.
Catherine Burke's body was discovered at a house in a quiet street in Muswell Hill last Thursday evening.
Residents said living next to the 40 foot high stinking mound was a 'living nightmare'.