The latest official statistics, published last week, show a fall in the quantity of Class A drugs seized between 2009/10 and 2010/11. But in a press release that pre-empted the publication of those figures, Green (pictured) used unofficial data for April-September 2011 to claim a significant rise in the amount seized thanks to the Border Agency’s work.

The UK Statistics Authority said the Home Office had been wrong to issue their figures early and that they were at odds with the official ones. Official statistics on drug seizures in April-September this year have not yet been published.

The Authority’s chairman, Michael Scholar, said the release – which was given to media outlets including the BBC and the Daily Mail, but not published on the Home Office’s website – appeared to have been produced “without any involvement by, and without the knowledge of, the department’s statisticians [and] is highly selective in its choice of statistics, in order, it seems, to show the UK Border Agency in a good light”.

If the Home Office’s motivation was to generate positive coverage before the release of figures showing a decline in the volume of seizures, this would be “highly corrosive and damaging to public confidence in official statistics”, said Scholar.

The release was inconsistent with the statutory Code of Practice on official statistics and with the Ministerial Code, he said.

A Home Office spokesperson said the figures were clearly labelled as “management information” – a caveat which comes in notes appended to the press release. “We take our responsibilities under the statistics code seriously and have promptly responded to Sir Michael Scholar,” the spokesperson said.