A council is attempting to catch a fly-tipping gang after spending £20,000 to remove 45 tonnes of waste from two dumps.
Vast piles of rubbish were dumped at locations on access roads leading off a busy stretch of the A6 near Market Harborough, Leicestershire.
The massive amount of household and construction waste was piled over a metre high in places and stretched along the entire length of the roads.
But the two illegal dumps only came to the attention of Harborough District Council after motorists complained they could see the waste from the main road.
Authorities spent three days removing the mountain of rubbish in the biggest single incident of fly-tipping the authority has ever had to tackle.
The council believes the waste was dumped over a period of several months.
The incident is being treated as a criminal offence and the council is appealing for information to track down those responsible.
Councillor Phil King, leader of Harborough District Council, said: “It is a big criminal operation. It is outrageous behaviour and residents of our district want us to keep it clean as we can.
“We have to get the evidence together and find out, if we can, who did this. We have used CCTV in the past to catch fly-tippers and monitor hotspots for people dumping rubbish.
“We are going through the waste to see if there are leads and clues there in an effort to try and bring these criminals to justice. If we catch who has done this then we'll do our best to make them pay for the cost of cleaning it up.”
Council workers have erected bollards to stop fly-tippers driving up the two access roads.
A council spokesperson added: “The council is continuing to investigate this incident.
“We are appealing for witnesses or any dash-cam footage which may help with our investigation.”