More than half a million households using Hotpoint and Indesit washing machines have been urged to immediately unplug the appliances as Whirlpool prepares to recall them over a fire-risk flaw.
The firm said as many as 519,000 washing machines sold under the Hotpoint and Indesit brands in the UK between October 2014 and February 2018 could be affected by the flaw with the door-locking system that could lead to them overheating and potentially catching fire.
It urged owners of appliances bought since 2014 to contact Whirlpool immediately to check if their washing machine is one of the models affected, acknowledging that the timing of the alert would cause "inconvenience and concern" to hundreds of thousands of consumers over the Christmas period.
However, the firm's website and helpline were promptly overwhelmed by the volume of customers seeking information.
We are experiencing technical problems with our website and customer service hotline, and are working to fix the issues as soon as possible. We will let you know as soon as they are live again. Please find affected model numbers below. Our sincere apologies for the inconvenience. pic.twitter.com/gfmIY9Lsvj
— Whirlpool UK (@WhirlpoolUK) December 17, 2019
Whirlpool said it was working at "full speed" as it prepares to officially begin the recall in early January.
In the meantime, it advised consumers to unplug their washing machines and not use them.
Those who chose to continue using their machines should only use cold water cycles of 20C or lower as this significantly reduces the risk, Whirlpool said.
This is because the issue is associated with the washing machine's heating element being activated during washing cycles above 20C.
Under the recall, all affected customers will have the choice of either a free-of-charge like-for-like replacement washing machine, or a free-of-charge in-home repair of their existing appliance.
Whirlpool Corporation vice president Jeff Noel said: "We sincerely apologise for the inconvenience and concern this may cause to our customers, particularly over the Christmas period, but we hope people will understand that we are taking action because people's safety is our top priority.
"Preparing for a recall of this scale is a complex operation and we are working tirelessly to ensure we are ready to start offering replacements or repairs to our customers from early January."
Sue Davies, strategic policy adviser at consumer group Which?, said: "This safety alert will cause huge disruption for millions of people who will have no washing machine over Christmas, and following the tumble dryer scandal, leaves Whirlpool's reputation as a company that can be trusted on product safety in tatters.
"People will rightly be asking what Whirlpool knew about these fire-risk machines and when, so there must now be a thorough investigation into this public safety issue. We know the company has a track record for appearing to put corporate reputation ahead of public safety in its disgraceful handling of the unsafe tumble dryer crisis."
Consumers can check if their washing machine is affected by visiting https://washingmachinerecall.whirlpool.co.uk. This site includes an online model checker tool, as well as a full list of model numbers.
Alternatively, customers can call Whirlpool's freephone hotline 0800 316 1442 where an adviser can assist with checking their model and providing further information.
To check if a washing machine is potentially affected, customers will need both the model number and the serial number of the appliance. Both of these codes can be found inside the door, or alternatively on a label on the rear of the appliance.
Whirlpool said the issue was identified by its safety team, adding that "no serious injuries have been reported".
The latest recall comes after the company finally launched a full recall involving 500,000 dryers in July.
The company acted after being criticised for resisting demands for a full recall and instead carrying out a lengthy "safety campaign" that saw 1.7 million products modified instead.
That earlier recall related to certain models of Hotpoint, Indesit, Creda, Swan and Proline dryers built between 2004 and 2015.
In November, MPs said it was "extraordinary" that as many as 800,000 of the defective dryers could still remain in people's homes four years after Whirlpool revealed they were a fire risk.
A Business, Energy and Industrial Strategy (BEIS) Committee investigation into the firm criticised the company for its slow response in modifying or replacing faulty machines while also condemning the firm's use of non-disclosure agreements (NDAs) to "silence customers".
Whirlpool had earlier revealed that, in recent years, it had logged 54 fires in its tumble dryers and admitted that three of those were models which had already been modified.
The BEIS committee also expressed concerns, shared by safety organisations, about the safety of Whirlpool's modification.
The report called on the Government to press ahead with a new review of the safety of Whirlpool's modification and to investigate other possible sources of fires in Whirlpool's tumble dryers.
The BEIS report followed Grenfell Tower inquiry chairman Sir Martin Moore-Bick saying he had "no doubt" that the fire was started by an electrical fault in a Hotpoint fridge-freezer, and dismissed a "fanciful" claim by Whirlpool that the fire could have been sparked by a discarded cigarette.