Different plastics could soon be thrown in the same recycling bin without needing to be separated, scientists say.

Plastic milk bottles are made from high density polyethylene (HDPE) whereas margarine tubs are made from polypropylene.

These two plastics cannot currently be recycled together so have to be separated by households or at the recycling centre.

This process can mean that plastic ends up in landfill because the batch becomes accidentally contaminated with several types of the material.

Scientists and engineers at the University of Bath’s Centre for Sustainable Chemical Technologies and Manchester University are investigating ways of chemically breaking down mixtures of plastic into their constituent molecules.

These can then be used to manufacture new plastics or other high-value products.

Professor Matthew Davidson, director of the Centre for Sustainable Chemical Technologies at Bath, said: “Currently only about one third of plastic food packaging in the UK is recycled.

“The UK Government aims to increase that to 75% by 2035.

“Part of this problem is that plastics have to be separated into different types as each type has different properties and they can’t be recycled together.

“Our colleagues in Manchester have already demonstrated a process to recover the chemical value from waste plastics and, together, we aim to develop this further in order to develop new technology for mixed plastics waste.

“This means in the not-too-distant future people will be able to throw all their plastics in the same recycling bin without worrying about separating them.

“This could make a big difference to recycling rates and help us solve the urgent problem of plastic waste.”

This project is one of seven being tackled by a consortium of UK universities and industrial partners, led by the University of Bath.

These aim to develop new catalysts to enable more sustainable manufacturing and promote a circular economy, where waste materials are reused or recycled instead of being thrown away.