Two more people have been arrested as protests continue at a lake where waste from a power station is being dumped.
Pumping of waste into Thrupp Lake is due to start later this year
Environmental campaigners are furious that RWE Npower is going to fill Radley Lakes in Oxfordshire with waste ash from Didcot Power Station.
The Save Radley Lakes group claim the area is home to rare species but the company said it was disposing of the ash "in a responsible way".
Two men - aged 36 and 43 - were arrested by police on Thursday.
The 36-year-old was released without charge but the other man is still in police custody.
He was arrested for failing to provide a name and address to a police officer.
On Wednesday, a 40-year-old man was arrested on suspicion of aggravated trespass.
Dr Robert Eeles, who took part in the protest on Thursday, said that although there were only seven protesters, Npower had more than a dozen masked security officers patrolling the area and there was a constant police presence.