Millions of Brits at risk of losing £300 by not doing this

Millions may be unknowingly carrying bank cards that are technically invalid, leaving them open to fraud at a time when card crime is surging.

More than three quarters of adults have failed to sign the signature strip on the back of their debit or credit card, according to new research by MoneySuperMarket.

Experts warn that this basic step matters, even in the age of contactless payments. The study found that just 24% of people have signed their card, meaning 76% are carrying cards that are technically invalid.

Even more striking, 94% of respondents said they were unaware that an unsigned card could be considered invalid at all.

Worryingly, only 24% said they regularly carry and use physical cards for payments, suggesting many may not even realise their card is missing this key security feature.

The warning comes as card fraud continues to rise sharply. Between January and June 2025, more than two million card fraud incidents were reported in the UK, while so-called card-not-present fraud jumped by 22%, making it easier for criminals to misuse stolen card details online or in shops.

Victims typically lose around £300 per incident, and reclaiming that money is becoming increasingly difficult. With AI-generated fake identities on the rise, fraud prevention service Cifas recorded more than 118,000 cases in the first half of 2025 alone.

Experts say an unsigned card can make matters worse if a card is lost or stolen, potentially complicating disputes with banks. Kara Gammell, credit expert at MoneySuperMarket, said: “Your signature might feel like a small detail, but it’s actually an important security step.

“It helps confirm that you authorised a transaction and gives you an extra layer of protection if something goes wrong.”

She added: “Even in an age where most payments happen through chip-and-PIN or contactless payments, your signature still matters. If your card is ever lost or stolen, an unsigned card is far easier for someone to misuse – and harder for you to dispute.

“It only takes a few seconds, but signing your card could give you valuable protection if the worst happens – and that extra peace of mind is always worth it.”

To highlight the issue, MoneySuperMarket has teamed up with handwriting expert and graphologist Tracey Trussell, who says the way you sign can also make a difference. She advises cardholders to keep their signature natural and avoid overthinking it.

“You don’t need to overthink it – just write as you would normally. Your handwriting is naturally full of unique patterns, and those subtle differences create authenticity,” she said.

Speed also matters, she explained, adding: “The key is to write quickly. Speed is difficult to replicate, and someone trying to copy your signature will write more slowly and carefully, struggling to reproduce the natural look of your signature. So, don’t worry too much about appearances and don’t hold back. A natural, flowing movement is difficult to fabricate and imitate.”

She said complexity can help too, saying: “Think of your signature like a password – the more complex, the better. Writing your full name, including a middle name if you have one, makes it harder to imitate. If your name is short, add a small distinguishing feature, such as a tiny full stop at the end. These details are often missed by forgers.”

She warned against overly simple signatures, adding: “One common mistake is making a signature too simple. A quick scribble is much easier to copy than one with structure and intention. Those small deviations from how you were taught to write should be embraced. It’s the tiny quirks in your writing that make a signature uniquely yours – and difficult for anyone else to replicate.”

Ms Trussell concluded: “Your signature is consciously designed and manufactured, so you’re in control. And it’s all the little quirks and deviations that should be treasured and celebrated because they make your handwriting more authentic and individual, and your signature legally binding and trustworthy.”