Police on Saturday prevented anti-capitalist activists from occupying the London Stock Exchange (LSE).
Several hundred protesters, who had organised the event online, were bidding to replicate the huge demonstrations which have been taking place in New York's Wall Street.
But police cordoned off Paternoster Square, where the Stock Exchange is located, as several hundred supporters of the Occupy London Stock Exchange movement tried to march in from adjacent St Paul's Cathedral.
A notice was put up stating that the square is private property and access would be restricted. Police sources said a High Court injunction had been taken out to prevent members of the public from accessing the square.
A spokesman for the protesters said: "We are doing this to challenge the bankers and the financial institutions which recklessly gambled our economy. This occupation and 20 other occupations all around the UK have been directly inspired by what's happening all across America and especially Wall Street."
The spokesman added that the protesters' intentions were to gain access to Paternoster Square, where they planned to hold an assembly to decide the nature of the occupation in the heart of London's financial district.
Activists carried banners with slogans such as "We are the 99%" and "Bankers got a bailout, we got sold out".
Among them was Lorena Fuentes, 27, a charity worker originally from Vancouver, Canada.
She said: "I'm here today because I can't see why you wouldn't be and I feel that this is one of the few moments in history where it's not a protest, it's an actual movement that's taken root. We're trying to challenge this myth that there are not enough resources to go around."
After the attempt to occupy Paternoster Square failed, protesters returned to their previous position in front of St Paul's Cathedral. Police confirmed they had made one arrest.