Campaign groups projected messages calling for an end to new fossil fuels onto the rig, which has been the focus of a missing persons investigation.
On Sunday night members of Extinction Rebellion (XR) and Stop Rosebank used projectors to show the messages ‘Stop Rosebank’, ‘No new oil’ and ‘Fossil fuels are killing us’ on the Valaris 121 rig in Dundee harbour.
It comes after 50-year-old Jason Thomas from Wales went missing from the jack-up while it was under tow to the city last month.
Officers from Police Scotland later boarded the rig to carry out enquiries and gather information to help establish the circumstances leading up to the incident, with the investigation now being led by the UK’s Health and Safety Executive (HSE).
Police told Energy Voice last week that the case was being treated as a missing persons enquiry and remains ongoing, but confirmed there are not believed to be any suspicious circumstances surrounding Mr Thomas’ disappearance.
The rig is scheduled to begin work with Petrofac later this summer, before moving onto a job with Shell some time in Q4.
A spokesperson for the groups said they had chosen the rig because it is moored close to public land, but were unaware of the recent incident on board.
“We are saddened to hear that anyone lost their life falling from the rig so recently,” they added.
It marks the latest action in an escalating campaign against the Equinor-led oil development west of Shetland, which has included protests at the Norwegian group’s offices in London and Aberdeen.
Retired midwife Anne Campbell said: “Equinor is applying to start drilling a new oilfield at Rosebank off Shetland.
“Instead, it should use its huge profits to accelerate development of the wind farms and other renewables projects in its portfolio.”
Sunday’s demonstration follows a letter signed by 200 major organisations including the Women’s Institute, Friends of the Earth, Greenpeace, Oxfam and the RSPB – as well as comedians Frankie Boyle and Aisling Bea – which urged Prime Minister Rishi Sunak to reject plans for the field.
Equinor and partners Siccar Point (20%) and Suncor Energy (40%) planning to deliver the development in two phases, targeting first oil at the end of 2026.
Siccar Point has previously said recoverable resources at the field could amount to some 300 million barrels of oil equivalent.
Equinor expects to make a final investment decision (FID) on Rosebank some time later this year.
Adding her name to the open letter, Ugandan UNICEF ambassador Vanessa Nakate said: ‘The need to end our global addiction to fossil fuels is crystal clear, yet if the UK government approves Rosebank, it will keep pumping out oil until 2051.
“The UK needs to take responsibility, care about people around the world who are already living with the climate crisis and protect young people and generations to come who will have to face the consequences of these decisions. It must reject Rosebank.”
Equinor has previously said the development has the potential to “strengthen energy security with oil and gas that is produced with a much lower carbon footprint than current UK production.”
“We aim to develop and operate projects such as Rosebank with the lowest possible carbon footprint while bringing the maximum value to society in the shape of UK investment, local jobs and energy security.
“The Rosebank project is estimated to bring £26.8 billion to the UK through tax payments and investments into the UK economy,” the company added.