Pin-hole cameras have been spotted in numerous ATMs, with police warning people to stay vigilant when withdrawing cash. Here's what to check if you suspect a cashpoint has been tampered with.

In some cases criminals place card or cash capture devices and PIN devices in or around ATMs to get quick access to your cash. A few sneaky scammers will even put on entire false fronts to capture unsuspecting people’s PINs and money, software company Fico told This is Money. They’re often really well disguised so have a thorough check of the ATM before you start using it.

You’re right to be concerned about an unusually bulky card slot, as this could contain a ‘skimmer’. This tool is attached to the ATM’s card slot that secretly takes your card details when you’re making a withdrawal. Apart from its width, it’s really difficult to distinguish it from a normal card slot. Keep an eye out for misaligned or misprinted stickers as they are often an attempt to cover up where a skimming device has been installed.

This may be a sign of a ‘Lebanese Loop’. Criminals will try and trap your card in the machine by placing a tiny plastic device or sleeve with a barb into the card reader so that, when you try and withdraw money, your card will get stuck. The ATM will keep asking for a PIN as it can’t read the card, leading you to believe that your card has been swallowed and walk away. That gives the fraudsters the perfect opportunity to swoop in and take your card.

Be wary if the PIN pad feels loose, thick or sponge-like. This crafty trick is known as ‘pin-pad overlay’; the real PIN pad is covered by a fake one which does record your PIN correctly just like any other machine, but also captures your details for the fraudster. In some cases numbers are instantly transferred by WiFi to a waiting accomplice so that they can record it and use it later.

Here's an example of a removable PIN pad slot used by fraudsters.

Police have warned that criminals can try to steal cash at ATMs using a simple screw. The screw jams the cash slot closed and no money comes out for the customer. The criminal approaches the machine after the customer leaves and simply removes the screw to find the trapped cash hidden in the slot. Older cash machines are the most vulnerable to this trick, so watch out.

Scammers are hiding tiny pinhole cameras in cash machines to record people's PINs, police have warned. The cameras have been spotted across central London. The most recent was hidden inside a fake cash-dispensing slot cover, filming the keypad as people entered their details.

Here's a close-up of a tampered ATM with the camera exposed.

Make sure you always cover your hand when you enter your PIN. Before you even enter your details, check the cash machine for loose parts, including the card slot and keypad. PC Matt Clarke from the City of London Police Crime Squad said: “If you spot anything unusual about a cash machine, or if there are signs of tampering, don't use it."

Make sure you always cover your hand when you enter your PIN.

Be aware of what’s going on around you. Don’t accept help from strangers and don’t get distracted. Scammers often work in teams and they rely on distraction to catch their victims out. It's a good idea not to use cash machines near a group of people who are inexplicably loitering. If something goes wrong they may become oddly helpful. When one is trying to assist you, the others may look at your PIN or swipe your card or cash.

“If you spot a suspicious device when using a cash point, report it to the bank concerned immediately and notify police. If you think a crime is in progress when you discover the device, call 999" is the police advice. Don’t try and remove anything yourself as the criminals in question could be hanging around near the machine and might confront you.