ower Bridge was stuck open for over an hour because of a mechanical fault, causing central London traffic to be gridlocked.

The historic bridge’s two arms were stuck at different angles after opening to allow ships to pass underneath on the River Thames on Saturday evening, with witnesses saying they failed to come down at the same time.

One Twitter user said: “So have been stood under a raised Tower Bridge for 15 mins now, hearing rumours it’s stuck.”

Another Twitter user posted a video of the incident, describing the electro-hydraulic system’s failure at the combined bascule and suspension bridge as a once in a lifetime moment.

Shortly after 5pm, City of London police tweeted to say the bridge was closed to pedestrians and traffic. “Mechanics are currently working hard to fix the bridge. Please find alternative routes,” the force said.

Police tweeted just over an hour later to say the bridge had reopened in both directions.