Defra has launched an investigation into claims that eggs are being inaccurately sold as free range.

It is concerned of possible illegal practices in the egg industry where some 1% of the three billion eggs produced each year in the UK are being incorrectly labelled, it said.

Meanwhile, salmonella contamination is present in one box in every 30 eggs produced outside the UK but sold in England, a separate study by the Food Standards Agency has found.