A night time jogger closed the Blackwall Tunnel in the early hours of this morning after running through the river crossing.
Transport for London announced shortly after 3am that it was closing the tunnel northbound "due to a pedestrian having a slow jog".
Their image appears to show a man running with a bag dangling from one hand.
The runner's stupid stunt was met with widespread derision on social network sites.
Tweeter @durranee wrote: "Let the traffic in, I'm sure it'll turn into a sprint."
And @lucyfrancis_tri joked: "took a wrong turn in training :-)"
Last week the tunnel - which is only open to motor vehicles - was closed by a dimwitted cyclist.