In a major u-turn for the green pioneer, Innocent has slashed the amount of rPET it uses in its smoothie bottles from 100% to 35% blaming a fall in the recycled plastic's quality and an "unpleasant blue tinge".

The move, which the company insisted was temporary, comes four years after Innocent claimed a world first when it put four smoothies into fully recycled bottles.

It had been prompted by a marked deterioration in the "aesthetic" quality of the recycled plastic over the past two years, claimed Innocent founder Richard Reed. The transparent plastic was now tainted by a blue-grey colour and the company had decided to reduce the amount used until the issue was resolved.

"It's not a permanent change the quality is just not good enough at the moment but we are working with our existing supplier to improve it," he said. "This problem is no-one's fault it's because of increased demand."

Quality had fallen as a result of supply shortages caused by heightened demand for recycled plastics and a deterioration in the quality of raw materials used to make them, said Reed. "Four years ago we were the only people buying bottles made from 100% recycled plastic," he said.

A 35% rPET content was still "a very positive and hugely beneficial industry target", he maintained, citing Wrap research.

Recycling experts agreed that it was much more challenging to make a 100% rPET bottle these days.

"There is not enough material to meet demand," said Chris Dow, MD of recycled plastic processor and supplier Closed Loop Recycling.

The industry needed Innocent to keep raising the bar on the use of sustainable materials and to set higher standards, he added. "But the situation in the UK is crazy at the moment there is not enough infrastructure or process plants to meet demand for recycled plastics and the quality is deteriorating."

Some food and drink companies were happy, however, to have the "specks and colours" remain in plastic packaging as this underscored how environmentally friendly the packaging was, he said.