London's historic Tower Bridge is to be repaired after technical problems meant its arms kept getting stuck last year.
The bridge's arms got stuck four times in 2005
The distinctive Victorian bridge, which spans the Thames, got stuck four times in 2005 because of problems with new sensors, a report found.
The arms, which raise to allow tall ships through, got stuck for ten hours last June - causing traffic chaos.
The faulty sensors fitted in 2002 are now being replaced as part of a £20,000 repair programme.
The report to the City of London Corporation, which manages the bridge, found they had gone wrong, causing the hydraulic pumps which raise and lower the arms - or bascules - to stop working.
The 112-year-old bridge is a major road crossing over the Thames in east London, used by about 40,000 people - motorists and pedestrians - a day.