A bid to remove anti-capitalist protesters who have been camped outside St Paul's Cathedral for a month is set to reach the High Court on Wednesday.

The City of London Corporation served an eviction notice on the activists which gave them until 6pm on Thursday to leave.

They were warned that they faced High Court action if they failed to quit their tents.

But demonstrators, who tore down the notices as soon as they were posted, vowed they would stay and said they were prepared to fight a potentially lengthy legal battle.

The corporation, the local authority which runs the Square Mile, has expressed concern over "worrying trends" at the camp, including late-night drinking, and said companies near the cathedral had complained about losing business.

Some of the tents are pitched on the footpath next to the shops surrounding the cathedral, with the remainder in the churchyard itself.

The notice said: "If any tents and other structures remain after 6pm on Thursday 17 November 2011, proceedings for possession and injunctions will be issued in the High Court of Justice without further notice.

"If granted, this would mean that you would be ordered by the High Court to remove the tents and any failure to do so could be a contempt of court."