A mountain of rubbish sits behind a metal fence in the village of Bickershaw, where it has remained for more than 20 months. For many residents, it is a physical manifestation of the north-south divide as well as a rotting, rat-infested symbol of a broken system in which organised criminal gangs make millions while communities endure the toxic impact of their trade.

The 25,000 tonnes of household and trade rubbish is one of the largest toxic waste dumps in the country. Unlike many illegal dumps that appear in woodlands, by rivers and on farmland, this one is in the heart of a residential street, right next to a primary school.

It is an environmental and public health hazard. Last summer the dump was on fire for nine days, forcing the school to shut and imprisoning residents in their homes to escape the fumes.

In the final few days of campaigning for the Makerfield byelection, the mountain of rubbish at the end of Bolton House Road has become something of a touchstone for local people of the promises being made by candidates.

Its continued existence, a year and eight months after the first lorries were seen dumping waste back in October 2024, shows how the north has been forgotten and left behind, some residents say.

They compare the failure to clear up the waste to the swift response of the authorities when a mountain of illegally dumped waste was discovered in Kidlington, Oxfordshire, in the south of England, last year. Within weeks, after parliamentary interventions, the Environment Agency (EA) announced it would spend millions to clear up the dump, in a departure from its usual practice of pursuing the criminal gangs and forcing landowners to pay for the removal of rubbish on their land. The cleanup is now well under way.

“If you look at the Oxfordshire one, that got agreed to be tidied up relatively quickly, and that was due to it being a fire hazard,” said Nicha Rowson, a beautician who lives a few doors away from the Bickershaw dump. “Well, this has already been on fire, for nine days, so it’s a north and south divide yet again.”

Many residents acknowledge that the outgoing Labour MP for Makerfield, Josh Simons, actively and publicly campaigned to get the dump cleared by the EA. His efforts succeeded when the government announced earlier this year that the agency would clear up the dump at a cost of millions to the taxpayer. But today there is no sign of the mountain of rubbish being removed.

The Manchester mayor, Andy Burnham, who hopes to retain the seat for Labour and fight off Reform UK’s Robert Kenyon in the byelection on 18 June, is keenly aware of the impact of the illegal dump on local people. He has mentioned it in the election leaflets posted through doors in the area and worked with Simons to try to force the authorities to remove it.

Reform, meanwhile, has been quick to capitalise, calling the dump an example of Britain’s decline under successive Conservative and Labour governments.

On Wednesday, Reform’s deputy leader, Richard Tice, said the party would hold a “national action day” on 4 July to clean up litter in communities and tackle waste crime by increasing fines and enforcement action. “Too many communities are being left to deal with litter and fly-tipping, which has become socially acceptable, while those responsible face little consequence for their actions,” Tice said.

Signs of support for Reform in Bickershaw were not obvious, however. A couple of houses nearest the dump had Reform placards in the garden but the occupiers were either not home or not keen to talk when the Guardian visited. One woman, getting into her car, said as she departed: “It’ll still be there in five years’ time.”

Most local people appeared to see Burnham – who has repeatedly presented himself as a voice for the north, a local champion, and a Westminster antagonist – as their best hope of getting the illegal dump cleared.

Rowson said: “Andy’s already helped me with the tip, he’s already been pushing to get it tidied up, so for Josh and Andy they’ve given me the confidence that they’ll carry on doing what they have been doing for me.” She favours the idea of Burnham as prime minister, because, she said, “I think he’ll definitely change that north and south divide; that’s the big one”.

Her neighbour, 82-year-old Doris, said she had little confidence that the dump would be removed, but she too was putting her faith in Burnham. “Well, he’s one of us,” she said. “He’s one of us, so I think he will do something.”

Colin Peters, who worked in IT before he retired, also planned to vote for Burnham. As well as objecting to the smell from the dump, Peters said it was affecting the price of properties.

A large section of the waste dump at Bickershaw is on land now owned by the duchy of Lancaster after it reverted to its ownership when no one could be traced as owners.

Peters remarked that he “could not see King Charles coming up with his bucket and spade” to shift the rubbish and it was Burnham whom he believed could help.

“He’s the only one, out of all the bumf we’ve been getting through the post, who’s actually mentioned [the dump],” he said. “None of the others have actually mentioned it, so does that tell you he might be the one who’s going to actually do something, or listen to people?”

He added: “He’s obviously from this area, so he might actually put things forward with more to do with the north-west of the UK, rather than everything being concentrated in the south-east and south.”

The ordeal for residents in Bickershaw began in October 2024 when lorries started arriving in Bolton House Road to dump rubbish. By January 2025 their numbers had grown to 20 or 30 lorries a day. Criminal gangs make millions by diverting rubbish to illegal sites and pocketing the landfill tax, which stands at £130.75 a tonne. The cost to the economy of a crime labelled as the new narcotics is about £1bn a year in cleanup costs, lost legitimate business revenue and evaded taxes.

“It’s been horrible,” Rowson said. “In winter it was more like a methaney smell, summer last year it was like a proper bad rotting smell. I’ve had rats in my house, we’ve had them in the cars. My youngest isn’t living with me at the moment, he’s spending five, six days at his nan’s, because when the smell is bad, it makes him sick.”

Part of the dump encroaches on the fields used by children at the primary school. Marilyn Naylor, who lives opposite the school fields, said the smell from the dump had stopped the children from playing outside in the past.

“It’s a nightmare, really,” she said. “We seemed to be getting somewhere, and then [Simons] left, so we’ve no idea.”

She too is pinning her hopes on Burnham. “I mean, he’s done so much for Manchester, hasn’t he?” she said. “I think the problem now is when it’s being said that he’s only doing this to get in, which he may be, but he has to get in somewhere, doesn’t he?”

The duchy of Lancaster said: “We remain fully committed to working with Wigan council and the Environment Agency to address this issue and to counter the impact of illegal waste tipping.”

The EA said Defra officials were in regular contact with Wigan council and local people to ensure the cleanup could move as quickly as possible, with important steps to be taken before proceeding to clearing up the site. “Once these steps have been completed, then the clearance operation should be able to begin swiftly,” it said.