One of the co-founders of Extinction Rebellion has denied planning to vandalise the headquarters of trade unions.
Roger Hallam, 54, of Wandsworth, south-west London, was one of five people arrested by the Metropolitan Police and remanded in custody in late August.
On Tuesday, Wood Green Crown Court heard the charge relates to an alleged plan to damage the buildings of trade unions with paint.
The court was told the plot was part of work by the political party Beyond Politics, in which Hallam is heavily involved.
Prosecutor Diana Wilson said they planned to target the buildings, including the offices of the British Medical Association, for failing to promote measures to prevent climate change.
The BMA is the professional body that represents doctors, and has its headquarters in Tavistock Square, in Bloomsbury.
Hallam was arrested on August 24 before being charged with conspiracy to damage property the following day.
Diana Warner, 61; Ferhat Ulusu, 42; Holly Brentnall, 29, and Steven Nunn, 56, were also arrested and charged.
Hallam appeared via video link from Pentonville Prison, wearing a grey sweatshirt, to deny the charge.
The court was told Hallam was being held in poor conditions, including the presence of cockroaches, which formed part of a successful application for bail.
Hallam, of Putney Bridge Road, south London; Warner, of Filton Avenue, Bristol, and Ulusu, of Mount Pleasant, east London, deny the conspiracy charge.
They will appear again at Wood Green Crown Court on November 27.
Brentnall, of Clonmell Road, north London, and Nunn, of Longdon upon Tern, Telford, have not entered pleas and will appear at the same court on November 6.