One in ten websites send spam e-mail, says Spam Ratings.
Spam Ratings said Argos, Ticketmaster and Money Supermarket were among the offenders.
Two in five of spam e-mails that contain malware feature pharmaceutical or sex-related content, while 35 percent are related to finance and 15 percent are phishing emails that impersonate bona fide sites in a bid to steal log-in details.
Three-quarters of emails from the UK's top 10,000 websites are either unwanted, nuisance or dangerous spam e-mails.
"Spam is a nasty and dangerous disease that has turned into an epidemic in the UK," said Andy Yates, co-founder of Spam Ratings.
"Websites are the main cause and the main way the disease has spread. Too many websites sell data to third parties and are the source of the huge growth in unwanted and dangerous emails. "
Yates urged consumers to web users to be when shopping online or signing up to websites.
The research firm has also started a Stop Spam Abuse campaign on Facebook.
"Any websites mentioned on our Facebook 'wall of shame' will be investigated and, if appropriate, reported to the appropriate trade or law enforcement body," Yates said.
See also: 51% of firms send unwanted spam emails
This story, "1 in 10 Websites Spews Spam" was originally published by PC Advisor (UK).