FoE campaigners will distribute information leaflets outside supermarkets across the country, and encourage members of the public to lobby retailers to boycott suppliers that use carbendazim and other potentially harmful chemicals.

An analysis of government data on pesticide residues shows that carbendazim has been discovered in a variety of fruit and vegetables including apples, oranges, peas and mushrooms.

The produce was sold in supermarkets throughout the UK.

Carbendazim, designed to kill fungi, was recently listed by the German Federal Government as a potential human hormone-disrupting chemical.

The chemical has been shown to damage the production of sperm in rats and in the development of the testicles. It has also been shown to damage growth of mammals in the womb.

Data from the Ministry of Agriculture, Fisheries and Food shows that levels of carbendazim do not exceed safety official safety limits.

However, FoE is concerned that disruption of the reproductive hormones may still be caused by lower levels of the chemical.

'Outrageous finding'

Sandra Bell, pesticides campaigner at Friends of the Earth, said: "It is outrageous that pesticides which could cause long term damage to our children's development are being sprayed on our food.

"The government must ban the use of carbendazim at once."

Ms Bell said food manufacturers and supermarkets should come clean and tell customers what the food they eat is sprayed with and what residues they contain.

"They should stop their suppliers using dodgy chemicals like carbendazim. That is the only way that consumers can be sure they are eating real food."

A spokeswoman for MAFF said the use of all pesticides was tightly controlled to ensure that they posed no threat to human health, and that there was no evidence that carbendazim was present in levels that posed any significant danger.

Officials are now considering the need for tighter import controls on produce grown outside the European Union.

Carbendazim is the most commonly used fungicide in the UK.