A key inner city brownfield site earmarked for up to 400 homes could now be unsuitable for development after 51,000 tonnes of building waste was dumped there without permission, planners have warned.

The site of a now-demolished factory in Lidget Green, Bradford, was being used for unauthorised landfill throughout much of last year, authorities say.

The waste is said to have raised the ground levels by up to six metres in places and has put at risk redeveloping the Northside Road site for much-needed housing.

The company behind the dumping has insisted it was simply making the site suitable for development by levelling it and removing contamination.

But Bradford Council disagrees and the Environment Agency has now ordered it to remove some of the waste.

The site was formerly a Rentokil Initial factory. It closed in 2008 and was later demolished.

In 2012 it was given outline planning permission, jointly with a neighbouring patch of land, for up to 400 homes.

But last year the Council raised concerns that the site was being used to stockpile construction and demolition waste.

As a result, the company working there, Rotherham-based Peakstone Aggregates, applied for partly-retrospective planning permission for site clearance, remediation and landfill.

In its application, Peakstone said it had already brought in 51,280 tonnes of materials as it readied the site for a future developer, and wanted to bring in another 40,000 tonnes.

It said: “To leave the site with severe drops and uneven surfaces would have left the site in an unsafe condition.”

But this application was refused by Council planners last November, who poured water on the idea that the work would enable homes to be built.

In his refusal notice, assistant director for planning Julian Jackson said: “There is no evidence that the deposit of inert waste at the site will result in the beneficial restoration and reclamation of the site for future development.”

Instead, planners said they were concerned that the land levels had actually risen so high, there was a danger that it would be no longer suitable for development as any properties could be overbearing.

The Environment Agency also raised concerns that the “proposed development would pose an unacceptable risk of pollution of groundwater” as there was no proof the site was suitable for a landfill.

Now the Environment Agency has issued an enforcement notice, saying some of the construction and demolition waste must be removed.

A Bradford Council spokesman said: “Our planning enforcement team are working closely with them [the Environment Agency] to review the situation and ensure any appropriate action is taken.”

Councillor Val Slater, executive member for housing and planning, said homes in Bradford were badly needed and this situation was “not helpful”.

She said: “I would be concerned if what they’ve done does put the development of the site for housing into any doubt. We do need those homes.

“It’s a key brownfield site in the inner city for development, which is what people have been pushing for.”

Peakstone Aggregates project manager Andy Jones said landowner Frankhill Limited had asked for the site to be made suitable for development by clearing it, removing land contamination and filling in voids.

He said the company had obtained a certificate of exemption from the Environment Agency allowing it to use building waste for this purpose.

He said the site was tested regularly to monitor contamination levels, and contaminated soil from the site’s industrial past had been removed.

He said: “Where bits of contamination were found, it has all been excavated out and treated.”

Mr Jones said when it was told its activities were not covered by the existing planning consent, it had put in its further application and when this was refused, it had immediately stopped work there.

He said: “No more work on site has been carried out at all, since the planning decision. It is still an ongoing process with them and the Environment Agency.”

Mr Jones said Peakstone Aggregates had proof the land levels had not changed significantly since it had been a working factory, and said it disputed the suggestion that it was now too high for housing.

He said: “We are quite happy with the levels we have got to at this moment in time, but we won’t do any more work on site until it has been agreed with the Council and the Environment Agency.

“We can prove categorically that the levels are very similar to where they were.”

Mr Jones said the firm was in a constructive dialogue with the authorities to resolve the matter.

He said: “Everybody’s working together to come to a good solution so that site can be developed. I think it will make a nice site.”

In a report to planners last November, the Environment Agency said the company’s exemption certificate did not cover what was happening at the site, and an environmental permit would be required.

An Environment Agency spokesman has confirmed to the Telegraph & Argus the site still did not hold a permit, but because they were in the middle of a live investigation, the agency couldn’t comment further.

Ward councillor John Godward (Lab, Great Horton), said Peakstone Aggregates should remove the waste they had brought in.

He said: “They should be made to put it right. It won’t harm them. They shouldn’t have done it.”

Landowner Frankhill Limited, which is based in the Isle of Man, could not be reached for comment.