The northbound traffic on Dartmouth Road was just nuts yesterday morning. My barber said she was told that TfL had been messing around with the Dartmouth/London Rd sequence but even if that's true the traffic still looked bad going up London Road, so Sydenham Rise could be the culprit.

I've reported the Co-op lights to TfL before and they said there was a problem with the pedestrian crossing button box and they fixed it within days, so it could be something as simple as that. Always worth writing to them if you can spot a traffic light bottleneck.