Activists from Disabled People Against Cuts (DPAC) have blocked Westminster Bridge this afternoon.
People are standing and sitting on Westminster Bridge Road, blocking traffic, as they protest against cuts to benefits. The Metropolitan Police said they are aware of the demonstration and officers are on the scene.
Eyewitnesses said on Twitter that there was a "heavy police presence" at the demonstration.
Richard Benyon MP tweeted a picture of the protesters and police overseeing them. He later deleted the message, in the face of a backlash over his comments.
The Metropolitan Police said they were advising motorists to avoid the area if possible.