The site is next to the A34, a busy road running through cities including Oxford and Birmingham.
The land is just over three acres in size and is largely hidden by trees on all sides. The River Cherwell runs along its west side.
A satellite image from the end of March this year shows the site largely covered in grass.
By 13 June, it has completely transformed. The grass is replaced by dirt, and an excavator is caught in a satellite image.
On 17 August, the site remains largely unchanged apart from what appears to be a single lorry load of rubbish.
Five weeks later on 22 September, a 150-metre long and 15-metre wide area is piled with waste.
Drone footage filmed by Sky News shows that the waste dump is at least 10 metres high.
It would have taken tens of lorry loads to pile up this much waste in so little time.
Calum Miller, Liberal Democrat MP for Bicester and Woodstock, told Sky News it was the first time he had seen anything on this scale, questioning whether the Environmental Agency had the resources to deal with it. He said it’s the work of an organised crime group.
The cost of removing the waste is estimated to be more than the entire annual budget of the local council, which is around £25m.
With the site on a floodplain, Mr Miller listed what he saw as the three major environmental risks – waste being washed into the waterways, rain seeping through the waste and carrying toxins into the water and the danger of decomposing chemicals presenting a fire risk.
He said the police had used a helicopter with a heat-seeking camera and could see that some of the waste was indeed starting to decompose.
The Environment Agency told Sky News, “This is a sickening case of large-scale illegal waste dumping and we share the public’s disgust.”
A spokesperson said: “we took immediate action – issuing a cease and desist order in July. When the risk of further dumping emerged we subsequently secured a court order to close the site to prevent more waste from being illegally tipped.
“We have launched a major investigation and are working closely with the police and other partners to find those responsible and bring them to justice.”
Dr Amani Maalouf, a senior waste management researcher at the University of Oxford, told Sky News that the site is a “significant environment incident”.
“Once mixed waste interacts with a watercourse, microplastics, packaging residues, and other contaminants can disperse widely and persist in the environment,” she said.
The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.
