Tesco, the UK's largest supermarket group, has recalled five types of Christmas lights because of a potential electrical fault.
The company said that there had been no reports of dangerous incidents.
Customers should stop using the lights immediately, unplug them and return them to any Tesco store for a full refund or replacement," the firm said.
Tesco said the lights had been on sale since October and the fear was that some wires might become detached.
The products affected are:
* Tesco's 100 indoor multifunction frosted berry lights, model number 5056-36
* Tesco 100 indoor multifunction clear lights, model number 5056-06
* Tesco 100 indoor multifunction coloured lights, model number 5056-06
* Tesco 200 indoor multifunction clear lights, model number 5056-35
* Tesco 200 indoor multifunction coloured lights, model number 5056-35
The company said it was investigating why the products failed to meet its strict quality control procedures.
"It is unfortunate that on this occasion some of these products did not meet the requirements," the company said.