The inexorable rise of the free range egg continued this week with the news that four in 10 eggs sold at retail were now free range.

Sales rose by almost 20% in volume and 50% in value in February, according to British Lion eggs.

The overall egg market also rose 1% in volume and nearly 30% in value, with sales exceeding £58m during the month.

"The egg industry has become one of the most successful agricultural sectors by reacting to consumer demand and we are well prepared to supply additional free range eggs if the market demands it," said Andrew Parker, chairman of the British Egg Industry Council.