Leading retailers named and shamed in new report, as most likely to bombard customers with unwanted spam emails.
The worst offender was Arcadia Group, which sent an average of two emails a day to customers who signed up to its major high street names, working out at 394 over the six-month period.
The report, carried out by Spam Ratings, looked at emails sent by 100 leading and trusted UK brands over a six-month period. It found that more than half of UK online retailers fail to comply with email good practice guidelines and send large volumes of emails that users have not explicitly consented to receive.
PC World, Shop Direct-owned Woolworths.co.uk, Aldi and B&Q were named among some of the worst retailers for bombarding customers with spam emails, while Marks and Spencer was criticised for only including an 'opt out' option on its online registration forms.
The report also found that 44% of the retail brands analysed automatically opt-in consumers to receive emails and that 56% of the emails sent from the top 100 brands were not explicitly asked for by consumers.
According to Spam Ratings, only one-in-three UK brands meet email marketing best practice standards and don't send emails that customers have not explicitly asked for.
Spam Ratings co-founder Andy Yates said: "Trusted brands are making a big mistake by not acting responsibly, openly and fairly with customers. Businesses spend millions building brands and then seem intent on destroying them by sending millions of useless, unwanted emails."