With Britain's high streets fast approaching their busiest time of the year, the public are being offered free 'card defenders' in some areas to protect them against contactless card fraud.
The local council and police in St Albans, Hertfordshire, say they are concerned about criminals using hand-held readers to skim shoppers' card details to carry out 'electronic pickpocketing, fraud or identity theft.
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"Contactless payment cards have led to an increase in electronic pickpocketing," says the Community Safety Partnership.
"Criminals are using handheld card readers to skim payment details and sensitive information without the victim realising."
The Card Defender is an intelligent card sleeve holder that contains radio frequency ID blocking technology, and a card can't be read while it's inside.
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Leicester, too, is offering the card protectors free of charge, through the City & County Neighbourhood Watch Association. Meanwhile, other police forces, including Lancashire, are recommending that people buy their own; they are available online from sites including Amazon and eBay for as little as £1.
"At a supermarket checkout for example, if you were standing in close proximity to a person attempting to pay with a contactless card and their card was faulty (for any reason), the reading device will take the information/payment from any contactless card within its range."
Fraud prevention company Defender Note claims contactless cards are twice as vulnerable to fraud as traditional cards, with 18% of users saying they have fallen victim.
Contactless cards: twice the level of fraud
It's been shown - in theory - to be possible to steal money from the cards of people nearby using a hand-held reader, although there's no evidence that this has actually been happening.
However, the UK Card Association says there has never been a confirmed report of money stolen from a contactless card while it's still in the cardholder's possession in the UK.
And if a payment is taken fraudulently, it says, the money will be refunded unless the card-holder has been negligent.
Either way, the risk of a card being read by mistake at a crowded checkout is never greater than at this time of year - making a card protector a sensible idea.