Hacker leaks Cortina Watch’s data online, including customer details and sales tactics

Ms Joanne Wong, vice-president of international markets at cyber-security firm LogRhythm, stressed that “prevention is better than cure”.

She said: “In this digital environment, it is critical for companies to take up a preventive approach to cyber security. No industry is completely immune to cyber attack, and virtually every sector… faces the risk of an attack.”

She said the leaked information, including the purported pricing mark-ups, could influence customers’ purchasing decisions and impact the retailer’s reputation.

At the same time, she said affected customers needed to act decisively and pay extra attention to any possible scams or phishing attempts they could receive in the aftermath.