Organic egg sales have slumped because retail prices are too high, according to Waitrose.

Speaking at an organic egg conference in Derbyshire a fortnight ago, Quentin Clark, the supermarket's poultry, fish and egg buyer, said rising shelf prices had encouraged consumers to trade down to free-range.

His comments came as TNS figures were released showing organic egg sales had fallen 1.5% to £34m in the year to 20 May, while free-range egg sales grew 12% to £270m.

"There's been a slow decrease in the growth of organic egg sales," said Clark. "I don't think there's anything more to that than price - they have become very expensive." The average organic egg now costs 26p - up from 20p this time last year.

However, the gloomy news on sales didn't seem to put off potential new egg producers at the conference, organised by Hi Peak Feeds. A spokesman said 11 delegates had shown an interest in setting up an organic egg business after the event.