Lego has halted a project to make bricks out of recycled drinks bottles – saying the new material would have caused higher carbon emissions, it has been reported.

The Danish toy giant announced in 2021 it was researching whether PET plastic, or polyethylene terephthalate – which does not degrade in quality when recycled, could be used to make building bricks.

If this worked, the material could have replaced oil-based acrylonitrile butadiene styrene (ABS), which is currently used in pieces.

However, the firm has told the Financial Times that PET plastic would cause higher carbon emissions over the product’s lifetime as it required new equipment.

Lego will instead look to improve the carbon footprint of ABS, the newspaper reported.

Tim Brooks, the Lego group’s head of sustainability, said PET plastic needed extra ingredients to give it safety and durability, as well as large quantities of energy to process and dry it.

He went on: “It’s like trying to make a bike out of wood rather than steel.”

Lego’s chief executive Niels Christiansen told the Financial Times it was hoped there would be a “magic material” to solve sustainability issues.

He added: “We tested hundreds and hundreds of materials. It’s just not been possible to find a material like that.”