The incident occurred immediately before 7.40 a.m. today (April 26) on the northbound portion.
Officers and London Ambulance Service crews responded and discovered a cyclist suffering from minor injuries.
Following the incident, no arrests were made.
Traffic mayhem caused by the Blackwall Tunnel crash: live updates
The Blackwall Tunnel was blocked while the incident was investigated, however it has now reopened.
Between Greenwich and A12 Poplar, there are currently “severe” delays.
Police were called at 07:38hrs on Wednesday, 26 April to reports of a collision at the entrance to the northbound section of the Blackwall Tunnel, SE10,” a Metropolitan Police spokeswoman said.
Police and the London Ambulance Service [LAS] were called.” A biker had collided with an automobile at the site. Minor injuries were received by the rider.
“No arrests were made.
“At 08:36 a.m., the tunnel reopened.”
