City of London police, who were supported by the Met, said 23 arrests were made during the "largely peaceful" eviction as bailiffs from City of London Corporation removed tents and equipment from outside St Paul's last night.
The action was taken five days after Occupy London was refused permission by the Court of Appeal to challenge orders evicting protesters.
Stuart Fraser, policy chairman of the City of London Corporation, said: "It is regrettable that it had to come to the need for removal but the High Court judgment speaks for itself. The site has now been cleared and the area is undergoing a deep clean."
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Police were called to a fight between two groups of people on the petrol station forecourt at Cobham services.
The barriers are part of a series of measures put in place by the Metropolitan Police.
Resident group Justice 4 Grenfell say they were not consulted and will raise concerns about the appointment at the highest level.