Two environmental campaigners have boarded an oil rig as it was being towed out to sea in the Cromarty Firth. Greenpeace activists said they scaled the Transocean rig Paul B Loyd Junior, contracted to BP, on Sunday evening. They are calling for BP to end drilling for new oil wells. BP said it shared the protesters' concerns about climate change and was "working every day to advance to a low carbon future". But it warned: "While we recognise the right for peaceful protest, the actions of this group are irresponsible and may put themselves and others unnecessarily at risk." Greenpeace said the 27,000-tonne rig owned by Transocean was on its way to the Vorlich field to drill new oil wells operated by BP.