London -Every day, hundreds of thousands of us pop into coffee shops. While we sip our cappuccinos, we may connect our smartphones to the cafes’ Wi-Fi network, and catch up with friends via services such as Facebook.

As well as socialising, we may use the time and free access to a wireless connection to get on top of our finances. That £75 you owe the plumber can be paid instantly by accessing your bank’s website or app. Transferring money from your savings account to your current account is nothing more than a few taps on your screen.

But what coffee drinkers do not suspect is that lurking among their fellow latte lovers are bank robbers. Unlike the figures of popular imagination, these thieves will not be wearing stockings over their head or brandishing a sawn-off shotgun.

Instead, the thief could be that smartly dressed middle-aged man hunched over his laptop, seemingly catching up on his emails.

Or maybe it’s the student in the corner, chatting to a friend on his phone while tapping at a tablet computer.

Unbeknown to you, this modern form of bank robber is silently harvesting all your private data. The only sign of his thievery is perhaps a little smile as your bank log-in details appear on his screen, ready for him to copy and paste before plundering your account within seconds of you finishing your coffee.

In short, you’ve just been mugged but you’ll only realise when you later go to a cash machine to withdraw some money, and discover that every penny in your account has been cleared out.

During an anxious phone call to the bank, you’ll learn that an online thief has hacked into your account and stolen all your money. Although the bank will usually restore your balance, they won’t be able to restore the feeling of security you had before the cyber robbery.

‘When I first found out that it had happened to me I felt utterly violated,’ says Pam Clover, 40, a marketing consultant and mother-of-three from Salisbury, Wiltshire.

After all, your bank details are some of the most private things you have, and somehow a complete stranger had gained access to mine. My first question was: How had he done it? Increasingly, the most likely answer to that question is through your smartphone. Although we like to think that our devices are secure, it is disturbingly easy for criminals to access them.