Environmental group Greenpeace has delayed departure from the Cromarty Firth in Scotland of a BP-chartered drilling rig in the UK sector of the North Sea after members boarded the semi-submersible unit as part of protests against oil and gas exploration.

Protestors climbed on board the Transocean-owned semi-submersible Paul B Loyd Jr in the firth north of Inverness, Scotland, and said they planned to potentially keep the action going “for days”.