The Environment Agency (EA) is on a mission to clear 21,000 tonnes of waste that was illegally dumped in one go in Kidlington.
The massive heap of hazardous rubbish, described by an MP as "threatening an environmental disaster", stretched 150m and was around 20ft (6m) deep in November last year.
Diggers and lorries can now be seen picking up and clearing rubbish from the site next to the A34 and River Cherwell near Kidlington.
However, the sheer scale of the dump, which is nearly 12 metres high in places and contains plastic, foam, tyres and wood, means the substantial operation will take another five months to complete.
The EA, which declared a critical incident into the enormous pile of waste back in November 2025, started the clean up in April this year.
It has said the total operation is expected to cost around £7 million - but the agency is hoping to reclaim this money in court by seizing money from the criminals who illegally dumped the waste.
To date, four men have been arrested as part of the EA's criminal investigation.
The dump was first visited by the Environment Agency in July 2025.
Environmental campaigners have raised extreme concerns over the risk of toxic run-off entering the river Cherwell system- poisoning wildlife and threatening the health of the entire catchment.
A spokesperson for the Environment Agency told ITV: "Regular monitoring has found no evidence the River Cherwell has been polluted by waste, which is held back from the river by barriers and sandbags.
"We share the widespread anger about the waste dumped at Kidlington by shameless criminals."
5. Work has begun to remove the huge fly-tip dump near Kidlington
Diggers and lorries have begun the painstaking process of collecting and ferrying the rubbish away from the site, near the River Cherwell and A34 in Kidlington. However, the scale of the dump, which is nearly 12 metres high in places, means it will be months before the clean-up is complete. Photo: Tom Wren / SWNS
6. Britain's biggest ever fly tip
Shocking pictures show Britain's biggest ever fly tip - a pile of waste 500FT long dumped in one go. Photo: Tom Wren / SWNS
7. Work has begun to remove the huge fly-tip dump near Kidlington
Diggers and lorries have begun the painstaking process of collecting and ferrying the rubbish away from the site, near the River Cherwell and A34 in Kidlington. However, the scale of the dump, which is nearly 12 metres high in places, means it will be months before the clean-up is complete. Photo: Tom Wren / SWNS
8. Work has begun to remove the huge fly-tip dump near Kidlington
Diggers and lorries have begun the painstaking process of collecting and ferrying the rubbish away from the site, near the River Cherwell and A34 in Kidlington. However, the scale of the dump, which is nearly 12 metres high in places, means it will be months before the clean-up is complete. Photo: Tom Wren / SWNS