A critical incident has been declared over a 40ft-high mountain of waste after it was branded "utterly appalling" by Prime Minister Sir Keir Starmer.
The vast fly tip stretches for 150 metres in a field alongside the A34 in Kidlington, Oxfordshire, and it's feared that the nearby River Cherwell could be affected.
Sky News drone footage captured the sheer scale of the rubbish pile, which is thought to weigh hundreds of tonnes and comprise multiple lorry loads of waste.
The Environment Agency (EA) has declared a "critical incident" at the site, deploying additional officers to manage the area and progress its investigation.
The probe, dubbed Operation Nation, is following "several lines of inquiry" in a bid to hunt down those responsible for the fly tipping.
The agency will also erect additional barriers to reduce the risk of waste infecting the river if there is rainfall or flooding.
A temporary boom – a floating barrier on the water meant to contain the debris – is already in place.
It comes after Environment Secretary Emma Reynolds met with EA chief Philip Duffy to discuss the response to the site on Thursday.
Mr Duffy said: "The illegal tipping in Kidlington is totally abhorrent, and I share the local community's disgust at this case of environmental vandalism.
"We’ve declared a critical incident, meaning the EA is laser focused on finding those responsible and ensuring they face the full force of the law."
In her statement, the minister said: "The appalling illegal waste dumped in Kidlington is disgraceful and I know how strongly local people feel about the site.
"I've instructed the EA to take decisive action to reduce the risk of environmental harm and I am pleased they are now installing additional barriers to prevent pollution of the Cherwell.
"I am being regularly updated on the ongoing investigation and I want to see justice served for this disgusting crime."
The rubbish appears to comprise shredded domestic and commercial waste, like plastic and paper, which is non-hazardous, though it may also include items like batteries.
At the site this week, Sky spotted an old DVD, tooth floss and AA batteries at the edge of the waste pile.
The EA first visited the field at the beginning of July, after it was reported to them, and issued a cease-and-desist letter to stop further tipping.
Read more:
Analysis: How field became an illegal mountain of waste
Mystery foam on river sparks investigation
After more dumping was discovered, officers secured a court order to close down the site in October.
Anna Burns, the EA's director for the Thames area, said the mountain of waste grew so fast that most of it was in place before her organisation was alerted.
She said: "Most of the tipping happened before we were aware of it. As soon as we were aware, we acted quickly and decisively."
(c) Sky News 2025: Oxfordshire waste mountain by River Cherwell declared critical incident
Trump Ukraine peace plan is a surrender ultimatum for Zelensky
Starmer refuses to rule out manifesto-breaking tax rises in budget
Starmer demands investigation into Reform-Russia links after party's ex-Wales leader jailed
BBC board member resigns - and criticises 'governance issues' at top of corporation
Pilot killed after Indian fighter jet crashes at Dubai air show