It is now more than a year since the BBC Trust published a seminal report on the impartiality of the broadcaster's coverage of science, but there is clear evidence that it is still failing to address one of the main findings.

The author of the Trust's report, Steve Jones, Emeritus Professor of Human Genetics at University College London, warned about "false balance" in the BBC's reporting of issues, such as climate change, caused by "attempts to give a place to anyone, however unqualified, who claims an interest" in an issue.

In particular, Professor Jones questioned the application of the BBC's editorial guidelines, updated in October 2010, which require "due impartiality". His report stated:

"There is much debate within the BBC about impartiality as applied to science, with rather a split between its science specialists and its other elements. There may sometimes have been an over-rigid application of the guidelines to what is essentially a fact-based field. This can produce an adversarial attitude to science which allows minority, or even contrarian, views an undue place. The BBC has tried hard to find a suitable balance. I await with interest the results of the new Guidelines' emphasis on 'due weight' when making editorial judgements about impartiality. Whatever their influence there should be no attempt to give equal weight to opinion and to evidence."

However, a recent edition of The Daily Politics provided a stark demonstration that Professor Jones's report is being ignored in some parts of the BBC.

On 22 June, the programme featured a discussion about climate change featuring James Delingpole, who writes a 'sceptic' blog for the Daily Telegraph, and Andrew Pendleton, the head of campaigns at Friends of the Earth. The discussion was mediated by the show's host, Andrew Neil, with other contributions from two journalists, Peter Hitchens and Mary Ann Sieghart.

Although none of the five participants were climate scientists, or even have a degree in a science subject, Neil focused the largely fact-free discussion at one point on the question of whether the Earth has been warming over the past 15 years, and asked Delingpole and Pendleton to provide blogs that could be posted on the programme's website. The blogs were published earlier this week.

Neil comments in his introduction that neither blog has directly addressed the issue he raised. Pendleton, whose contribution was headed "global warming has not stopped", attempted to provide a link to a commentary I published earlier this year which points out that the rise in global temperature recorded since 1997 is not statistically significant, but also shows that there have been many such periods since 1970 when warming was undetectable from just 15 data points. The warming trend over the past 40 years is clear and statistically significant, but carrying out analyses only on small subsets of these data often means that the signal cannot be detected among the noise.

Delingpole, whose contribution was headed "global warming has stopped", merely observed that the rise in temperature over the past 15 years has not been statistically significant, before moving on to make a number of inaccurate and misleading statements clearly intended to undermine confidence in the scientific evidence. For instance, he claimed that the three warmest years on record in the United States all occurred before 1940, citing a 'sceptic' blog which alleges that the temperature measurements by NASA's Goddard Institute for Space Studies are wrong. In fact, the National Climatic Data Center shows that the three warmest years in the United States since records began in 1880 are 1998, 2006 and 1934.

When I drew attention to Delingpole's inaccuracy, The Daily Politics tweeted: "TV debate and blog give both sides a chance to air their views - readers can make up their own mind".

Ironically, Andrew Neil complained during the programme that it was usually activists who discuss recent temperature trends, yet The Daily Politics has rarely, if ever, included a climate scientist in any of its debates about global warming. And this is not the first time that the programme has subjected its audience to inaccurate and misleading information about climate change.

This again illustrates the systemic failing of The Daily Politics and other BBC programmes such as Newsnight and Today which attempt to deal with issues of evidence-based science as if they were simply opinion-driven politics, with two opponents clashing in an argument mediated by a presenter whose knowledge of the topic is so low that he or she cannot distinguish between fact and fiction.

But the BBC persists with this format practice because it, like the rest of the UK's media, is dominated by graduates in the arts and humanities who lack any insight into the culture and practices of science, and who appear to treat all information as if it were just a 'point of view'.

To correct this fundamental failing, the BBC should take note of an excellent new report on Delivering Trust: Impartiality and Objectivity in the Digital Age, by Richard Sambrook, the former director of its global news division.

Sambrook argues that there is an important distinction between 'impartiality' and 'objectivity', even though they are often used interchangeably: "impartiality relates to absence of bias and objectivity to identifying facts and evidence". If the BBC wants to retain the public's trust in its coverage of issues such as climate change, it needs to place greater value on objectivity as defined by Sambrook, and drop its ill-conceived fetish for impartiality between facts and opinions.

Bob Ward is policy and communications director at the Grantham Research Institute on Climate Change and the Environment at London School of Economics and Political Science.

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