Up to a fifth of waste people in Norfolk put in their recycling bins ends up being burned, figures have revealed.

Council bosses say between 15pc and 20pc of items put in doorstep recycling bins is "contaminated", which means it cannot be recycled.

Instead, it is taken to Lincolnshire where it is mixed with other materials to form fuel for kilns which make cement.

The Norfolk Waste Partnership, through which Norfolk’s county, district, borough and city councils work together to improve waste and recycling, said people putting dirty nappies in recycling bins was a particular problem.

In a statement, the partnership said: "Approximately 15pc to 20pc of what Norfolk residents put into their recycling bin, is not material that we can take for recycling.

"Common contaminants are black bags of general waste, dirty nappies, textiles and plastics such as toys.

"Not only is this a waste which then needs to be disposed of separately, but some items, such as the nappies, can contaminate the recyclable materials as well."

The waste is collected from the Materials Recycling Facility in Costessey and delivered to Lincolnshire where it is shredded and blended with other grades of waste material, including carpets.

That is then burned as a fuel for cement kilns around the Lincolnshire area.

Eastern Daily Press: Paul Neale, Green Norwich city councillor.Paul Neale, Green Norwich city councillor. (Image: Norwich City Council)

At a meeting of Norfolk County Council's cabinet on Monday, Green city councillor Paul Neale asked whether 'rigid plastics', such as garden furniture and children's toys, were recycled.

Andy Grant, cabinet member for environment at the council, which stopped collecting plastics at its recycling centres five years ago, confirmed rigid plastics were sent to energy from waste plants.

Eastern Daily Press: Andy Grant, Norfolk County Council cabinet member for environment and waste.Andy Grant, Norfolk County Council cabinet member for environment and waste. (Image: Norfolk Conservatives)

Mr Neale said: “I was relieved to hear that plastic collected from blue bins at the kerbside is recycled, as we all expect it to be.

"However, I was shocked and disappointed to hear rigid plastics, such as in garden furniture or a children’s toy, aren't recycled, but incinerated.

"If we’re to play our part in reaching climate neutrality by 2030, as the council has said it wants to do, Norfolk needs to do better.”

The government has said it will introduce new taxes to reduce unrecyclable plastic entering the waste stream.