An oil industry leader has accused Greenpeace of “undermining its own credibility” by reviving its protest on an oil rig in Cromarty Firth.

Deirdre Michie, chief executive of Oil and Gas UK (OGUK), said the re-occupation of the rig was “disappointing” and urged people to work constructively with the industry on climate change.

BP said it supported debate and peaceful demonstration, but labelled Greenpeace’s actions as “irresponsible”, accusing the campaign group of putting other people at risk.

It’s understood that the 92 crew members on the rig have had to stay in the accommodation unit most of the week for safety reasons.

Greenpeace said its protestors were “highly trained” climbers and that its quarrel was with BP, not the rig workers.

Two activists climbed onto the Paul B Loyd Jr rig at 4am today, defying an interdict obtained by the vessel owner, Transocean.

Last night, police thought they had ended the demonstration when they removed two other demonstrators following a stand-off lasting several hours.

The protest began on Sunday and has prevented the rig from going out to drill BP’s Vorlich well in the North Sea.

Commenting on the re-occupation, Ms Michie said: “This is disappointing and our industry, with its focus on safe operations will not condone these actions.

“By going back on board the rig, Greenpeace is undermining its own credibility and not helping to move the debate on.

“OGUK is focused on playing a constructive role in solving the UK’s dual energy challenge and we would urge anyone and everyone who wants to be part of the solution to work with us in resolving the challenges that we need to face together.”

The “dual challenge” is the need to reduce emissions, while keeping up with world demand for energy.

A BP spokesman said: “We continue to work with Transocean, Police Scotland and all relevant authorities to bring this reckless action by Greenpeace to a safe conclusion.

“We support debate, discussion and peaceful demonstration, but the irresponsible actions of this group are putting themselves and others unnecessarily at risk, while ignoring court orders and police action.”

Rosie Rogers, senior climate campaigner at Greenpeace UK, said: “We realise working on a rig is a tough job at the best of times – these are dedicated, hard-working people.

“Our argument remains with BP, which continues to fuel the climate emergency, not with the workers.

“Their skills and know-how will help build a climate friendly future, if the likes of BP would support them to do so.

“Instead, BP’s CEO Bob Dudley announced last year, “If someone said, ‘Here’s $10bn to invest in renewables,’ we wouldn’t know how to do it”.”

BP recently bought stakes in Europe’s largest solar network, Lightsource BP, and the UK’s biggest electrical charging network, Chargemaster.