Like the American progressive media establishment, Britain’s media has been beset with charges that liberal stories and research are promoted while conservative leaning stories and sources are eschewed and a new study claims to confirm the accusation.

The new study by the Centre for Policy Studies, a London-based, center-right think tank, says that it has compiled enough statistics to show the BBC’s left-wing bias.

“Our results suggest the BBC exhibits a left-of-centre bias in both the amount of coverage it gives to different opinions and the way in which these voices are represented,” said Oliver Latham, author of the Bias at the Beeb report.

The study, to be released in September, compared the BBC’s coverage of what has appeared in the Daily Telegraph, which is considered Britain’s Right wing paper, and that of the left-leaning Guardian. The report found that the BBC covered seven out of ten stories that appeared in the left-wing paper while only covering three out of ten from the right-wing paper.

But the more telling detail is how the BBC treats its sources.

Latham found that when the BBC quotes left-wing organizations or think tanks as its “experts” in a story, the information is usually presented without caveat. But when right of center organizations are cited the BBC issues what Latham calls “a health warning.” All too often, Latham found, the right of center organizations are noted as such and viewers are warned accordingly.

“In other words, the BBC seems to treat right-of-centre views as being more ‘extreme’ and in need of caveats than roughly equivalent left-of-centre views,” Latham said in the Sunday Times.

Latham also found that left-wing groups are often described in BBC news reports as “independent.”

“The implication seems to be that the BBC sees left-of-centre views as being more reliable than right-of-centre ones. Overall, the picture is that the existing accusations of bias at the BBC are supported by a more dispassionate, quantitative analysis” Latham said.

The BBC has been a subject of complaints of left-wing bias for decades. In 2005, for instance British columnist Melanie Phillips wrote that, “BBC journalism is trusted around the world–which is why its bias is of such momentous importance and has such potentially devastating consequences.”