Marks & Spencer has admitted it is “behind plan” on its pledge to increase organic food sales.

As part of its high-profile environmental and ethical programme Plan A, launched four years ago, the retailer said it wanted to triple sales of organic food in the UK and Republic of Ireland by 2012.

However, in a Plan A update last week, M&S conceded that sales had not only “continued to decline” in the past year, but that they were now lower than in 2005/06 its baseline year. “We aim to review our plans for organic food in 2011/12,” it added.

The decline in organic sales is being felt across the sector. In April, the Soil Association’s annual Organic Market Report revealed overall sales had fallen 5.9% in 2010 to £1.73bn as reduced customer spending took its toll.

Although M&S declined to provide specific sales figures, a spokesman said the pledge had been set “when the market was in a very different place”.

“Times have changed, but customers still want provenance,” he said. “In some cases, that’s organic, in others it’s British, MSC, higher welfare, free range or Fairtrade.”

Head of technology Paul Willgoss added that there were still pockets of strong demand for organic at M&S. “Organic foods are still popular in certain categories such as meat, vegetables and dairy, reflecting our organic customers’ desire to buy ingredients and cook from scratch,” he said.

Although it had failed to hit its organic target, the Plan A update revealed that of its 180 commitments, M&S had achieved 95 and was on track with 77. It had reduced carbon emissions by 13% since 2007 and fuel efficiency on food delivery fleets had improved by 22%. It had also hit its target of slashing packaging by more than 25% a year ahead of schedule.

Other achievements included rolling out its Food Supplier Sustainability Framework, banning the use of a further 20 pesticides and introducing a sustainable farming ­programme with 10,000 farmers and growers.