A group of environmental protesters have climbed to the top of two 75m (246ft) high chimney stacks at a gas-fired power station in Nottinghamshire.
Greenpeace said eight activists had scaled two of the chimney stacks at Staythorpe Power Station near Newark in a protest over the role gas played in setting electricity prices.
Nottinghamshire Police said four protesters came down before midday, while the others came down shortly after 16:30 BST. The eight activists were arrested for aggravated trespassing and remain in custody.
A spokesperson for RWE, the energy company which owns the facility, said the power station remained operational and the firm's priority was the safety of everyone on site.
Assistant Chief Constable Suk Verma said the force would work with the site's owner and key partners to prevent future security breaches.
"Our policing response has been guided by multi-agency principles and legislation, and we have worked closely with our partners in responding to this matter," he said.
A spokesperson for RWE said: "Early this morning, a group of protesters gained access to Staythorpe Power Station near Newark.
"At the time of the incident, the power station was operational and continues to produce power.
"As the situation evolves, our foremost priority is the safety and wellbeing of everyone on site, including our staff, contractors, and the protesters.
"We are closely monitoring the situation and working collaboratively with the relevant authorities to ensure that all necessary safety measures are in place."