Cashpoint

Shoppers looking for knock-down deals in Black Friday’s online extravaganza tomorrow, and next week on Cyber Monday, are being warned of the risk from cyber crooks.

One in four adults have been victims of online fraud, losing £646 on average, research from security software firm Sophos reveals.

People are leaving themselves at risk from online rogues because of simple mistakes they make.

Half don’t have different passwords for each online account, a fifth use family members’ birthdays and pet names as passwords, and one in 10 save passwords on shared computers.

So, to raise your defences:

■ Don’t use the same passwords for each online account and don’t use information that can be readily found online, such as pet names. Crooks will stalk you and your social media to collect all the information they need to gain access to your bank account or credit card.

■ Don’t auto-save passwords.

■ Never make financial transactions over free wi-fi offered in cafes, hotels and on trains.

■ Always ensure you have the latest anti-virus software on all devices.