Around 700,000 eggs from Dutch farms implicated in a contamination scare have been distributed to Britain, rather than the 21,000 first estimated, the Food Standards Agency (FSA) has said.
The FSA said investigations into the Fipronil incident in Europe suggested it was "very unlikely" that the eggs posed a risk to public health, and products affected in the UK were processed foods in which egg is one ingredient among many others, mostly used in sandwich fillings or other chilled foods.
It said some of the products made from these eggs will have had a short shelf life and will have already been consumed, but some were still within the expiry date and were being withdrawn by the businesses involved.
Many of the eggs were mixed with others which had not come from affected farms so Fipronil residues would be highly diluted, the FSA said.
The decision to withdraw the products was not due to food safety concerns but based on the fact that the pesticide is not authorised for use in food-producing animals.
The FSA said it had no evidence that eggs laid in the UK are contaminated or that Fipronil has been used inappropriately in the UK.
Testing of eggs on farms is under way across the UK and results to date for England and Wales show no exposure to Fipronil.
FSA chairwoman Heather Hancock said: "I'm confident that acting quickly is the right thing to do.
"The number of eggs involved is small in proportion to the number of eggs we eat, and it is very unlikely that there is a risk to public health.
"Based on the available evidence there is no need for people to change the way they consume or cook eggs. However, Fipronil is not legally allowed for use near food-producing animals and it shouldn't be there."
Aldi and Lidl stores in Germany, along with Dutch supermarkets, have already taken millions of eggs off their shelves.
Aldi said it was "purely precautionary" and added that those sold in its UK outlets are produced in Britain.
The scare started in the Netherlands and Belgium and it is thought that disinfectant used in products on chicken farms is at fault.
Belgian authorities admitted that a farm alerted them to possible contamination in June - several weeks before the scare became public knowledge - but they thought it was an isolated case.
Britain produces 85% of the eggs it consumes but imports almost two billion annually, the FSA added.
Reported adverse effects from consumption of Fipronil include sweating, nausea, vomiting, head and stomach pain, dizziness and seizures, according to the US National Pesticide Information Centre.
The British Egg Industry Council said: "British egg producers have reiterated the need for consumers and food producers to look for British Lion eggs and egg products following the FSA's announcement that some processed foods are being withdrawn from sale as they may have been made with non-UK eggs contaminated with Fipronil.
"Shell eggs on sale to consumers are not affected and the FSA says that there is no need for people to change the way they consume or cook eggs.
"All major UK retailers stock British Lion shell eggs and tests have shown that there is no risk from British eggs."