In July 2011 a BBC Trust review cited findings of an assessment by Professor Steve Jones of University College London. Jones found there was sometimes an "over-rigid" application of the editorial guidelines on impartiality in relation to science coverage, which failed to take into account what he regarded as the "non-contentious" nature of some stories and the need to avoid giving "undue attention to marginal opinion". Jones gave reporting of the safety of the MMR vaccine and more recent coverage of claims about the safety of genetically-modified crops and the existence of man-made climate change as examples. In 2017, the BBC apologised for allowing climate change denier Nigel Lawson to claim that global temperatures had not risen in the past decade on BBC Radio 4's "Today Programme", which the organisation acknowledged breached its editorial guidelines., and in 2018, Carbon Brief released an internal notice sent by Fran Unsworth, the BBC director of news and current affairs, that argued that the BBC's coverage of climate change often went against its own guidelines on accuracy and created a false balance with regard to impartiality: "Manmade climate change exists: If the science proves it we should report it... To achieve impartiality, you do not need to include outright deniers of climate change in BBC coverage, in the same way you would not have someone denying that Manchester United won 2–0 last Saturday. The referee has spoken".