Europe has overtaken Asia as the biggest source of email spam worldwide with Britain a major culprit, a report said Thursday.

Europe produced over a third of the world's total junk emails in the second quarter of 2010, slightly more than Asia, information technology security firm Sophos said. Asia had been ahead of Europe in the first quarter.

In terms of countries, it singled out Britain as a major contributor to Europe being given the dubious honour.

"The UK... saw a significant rise in the proportion of spam it relayed. With a total output of 4.6 percent of the world's spam, this puts the UK in fourth place overall compared with ninth earlier this year," the report said.

A steady increase in spam generation from France, Italy and Poland were also contributing factors leading to Europe's rise, it said.

Asian countries' rankings in the "hall of shame" generally fell, with both Vietnam and China dropping five places to tenth and twentieth, respectively.

The United States remained the world's single biggest generator of junk emails, accounting for 15.2 percent of total spam sent in the second quarter, up from 13.1 percent in the previous three months.

India came in second (7.7 percent) and Brazil took third place (5.5 percent).

South Korea (4.2 percent) came after Britain to be the world's fifth largest source of spam, followed by France (4.1 percent), Germany (4 percent), Italy (3.5 percent) and Russia (2.8 percent).

Sophos also said spam emails constituted 97 percent of all emails received by business email servers, "putting a strain on network resources and wasting a huge amount of time to lost productivity".

"It's an uphill struggle educating users about the dangers of clicking on links or attachments in spam mails, and that their computers may already be under the control of cybercriminals," said Sophos senior technology consultant Graham Cluley.

"Spam will continue to be a global problem for as long as it makes money for the spammers. It makes commercial sense for the criminals to continue if even a tiny proportion of recipients clicks on the links."