Police have temporarily closed Westminster Bridge after a “suspicious vehicle” was abandoned near the Houses of Parliament.
A spokesperson for the Metropolitan Police said officers mounted a routine response to the alert on Tuesday afternoon but found nothing suspicious.
Photos showed a bomb disposal robot being dispatched to investigate a car left in a bus lane on the bridge, which crosses the River Thames between popular attractions including the Sea Life Centre and London Eye, and Westminster.
Stewart McDonald, a Scottish National Party (SNP) MP, said part of the House of Commons library and terrace were evacuated and shut as the alert continued.
Tourists were seen gathering and taking photos of the scene at a security cordon, while river traffic passing underneath the bridge was also stopped.
Witnesses said that a man believed to be the driver of the car ended the bomb scare when he "sheepishly" walked back to collect it.
"I hope he has a very good reason," Tamara Murphy wrote on Twitter, while Tom Rogan called the man responsible a "dumbass" for causing a terror alert in central London.
Transport for London warned commuters that local bus routes and traffic would be subject to diversion and delayed as the closure was lifted.
The UK's terror threat level is currently set at severe, meaning an attack is considered "highly likely" and security forces are on high alert.
