Around 21,000 eggs from Dutch farms implicated in a contamination scare were distributed to Britain between March and June, the Food Standards Agency has said.
The public health threat to the UK from eggs possibly tainted by the pesticide Fipronil remains "very low" but the FSA is "urgently" investigating where they may have been sold.
The agency said its investigations indicate any affected products are no longer on sale, adding the "low level of potential exposure" means consumers should not be concerned.
Aldi and Lidl stores in Germany, along with Dutch supermarkets, have already taken millions of eggs off 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.
Dozens of farms are being checked in the Netherlands, while Belgium's food safety agency is probing how Fipronil might have entered eggs destined for supermarkets.
Belgian authorities admitted 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.
The British Egg Industry Council said there was no need to "change the way they cook or consume eggs" and that buyers should look for the British Lion mark to ensure they are getting "safe British eggs".
Fipronil is banned in products used around food-producing animals.
Reported adverse effects from consumption include sweating, nausea, vomiting, head and stomach pain, dizziness and seizures, according to the US National Pesticide Information Centre.