Traffic in central London was left gridlocked after Tower Bridge became stuck open for more than an hour due to a “mechanical fault”.

Social media users vented their frustration as the famous bridge failed to close after allowing a ship to pass through along the River Thames on Saturday afternoon.

Pictures showed queues of motorists and pedestrians waiting for at least an hour from both directions.

A witness told the PA news agency: “According to the security radios we overheard there are multiple failures.”

City of London Police said engineers rushed to fix the bridge as motorists were urged to find other routes.

Its Twitter account said: “Tower Bridge is currently closed to pedestrians and traffic, due to a mechanical fault.”

One social media user said: “I’ve been stuck here for nearly an hour now… #TowerBridge.”

Another commented: “Yep, tower bridge definitely stuck! One side started to come down but the other didn’t! #towerbridge #londontraffic.”

The bridge connects the Square Mile financial district to Southwark.

In 2005 police closed the bridge for 10 hours after a technical problem meant the arms could not be lowered.

A London Bridge spokesman has been approached to comment.