Just a heads up: there is a bit of politics with this story. The author was the head of the government advisory board that suggested changing the ratings (and thus penalties) of some drugs, but the subject was too dangerous to tackle politically. He criticised the government and got fired. A year later he publishes this report.

The Guardian's coverage ( http://www.guardian.co.uk/society/2010/nov/01/alcohol-more-h... ) knows that this report is likely to be attacked politically (regardless of merit) so it's no surprise they are using adjectives to cut off this attack. Note their use of words like "authoritative" and "respected" early in the article.