A man has jumped into the river Thames during a London cabbies' protest against the Olympic Road Network.
A picture published on Twitter appears to show a man diving headfirst into the Thames.
The protest- on Tower Bridge- is the second staged by black cab drivers against the ORN.
It brought traffic to a standstill in the area.
The man who jumped was picked up by a police boat.
A Met police spokesman said, "Around 4pm a man who was taking part in a planned demonstration jumped into the River Thames from Tower Bridge.Officers from the marine policing unit rescued the man. He has been arrested for a public order offence."
Black cab drivers have brought Westminster to a standstill.
They're protesting about not being allowed to use the Olympic Games Lanes- they say being excluded from them makes it impossible for them to do their job.
Even the slightest problem on London's roads during the Olympics could create "the perfect storm", former head of traffic at the Metropolitan Police Kevin Delaney has warned.
Mr Delaney, now head of road safety at the Institute of Advanced Motorists, said: "The problem with the Games lanes is that London's road network runs at, or very close to, capacity almost all day, almost every day of the year.
"Wherever the Games lanes are, they have reduced the amount of lanes for ordinary traffic. You are actually reducing the amount of road space for ordinary traffic."Unless everybody heeds the advice to not drive, there are problems. "