Police are sending text messages to over 70,000 people to warn them that they've fallen victim to online-banking scams, and telling them how to take action.

The messages are being sent by the Metropolitan Police as part of the UK's biggest ever anti-fraud crackdown, following an international operation to shut down a cyber-criminal service. The operation was led by the Met and involving law enforcement agencies in Europe, Australia, the US, Ukraine, and Canada, resulting in the arrest of 142 suspected cyber criminals.

Those arrested are suspected of being involved in conducting scams where they posed as representatives from banks -including Barclays, Santander, HSBC, Lloyds, Halifax, First Direct, Natwest, Nationwide and TSB -and tricked victims into handing over money, or one-time passcodes to access bank accounts.

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The scammers used a website called iSpoof, which allowed them to disguise their phone number so it appeared they were calling from a trusted source -something known as a spoofing attack.

Also: How to keep your bank details and finances more secure online

Criminals attempt to trick people into handing over money or providing sensitive information such as one-time pass codes to bank accounts. In the 12 months up to August 2022, around 10 million fraudulent calls were made globally via iSpoof, with around 3.5 million of those made in the UK. Of those, 350,000 calls lasted more than one minute and were made to 200,000 individuals. The 70,000 people being contacted are connected to calls made by individuals known to police, according to the BBC.

The attacks resulted in each victims losing an average of