From Hansard:

10 Dec 2007 : Column WA15


Revenue and Customs: Alcohol

Lord Avebury asked Her Majesty's Government:

What are the estimated average strengths used by HM Revenue and Customs to convert the quantities of beer, wine, spirits and cider respectively into hectolitres of pure alcohol in the published statistics on the amount of alcohol released for home consumption in each of the years 2000—01 to 2006—07. [HL529]
Lord Davies of Oldham: The estimated strengths used to convert quantities of beer, wine and cider in to hectolitres of alcohol are:

Wine (a) Beer Cider
2000-01 10.28 4.19 % 5.03 %
2001-02 10.07 4.16 % 5.02 %
2002-03 11.39 % 4.17 % 5.02 %
2003-04 11.74 % 4.19 % 5.02 %
2004-05 11.74 4.21 % 5.03 %
2005-06 11.77 % 4.17 % 5.03 %
2006-07 11.81 % 4.20 % 5.03 %

Note: (a) The increase in average strength in 2002-03 is caused by the reclassification of most “cooler/alcopops” to spirits-based “ready to drink”.
An average strength is not needed to produce the quantities of pure alcohol for spirits as the duty is charged on the quantity of alcohol released for consumption.

I have written to the Minister pointing out that the average strength of wine sold in Majestic, one of the UK's biggest retailers, is 13.5%, and there's no reason to think their wines aren't typical. Therefore the Customs & Revenue statistics, which seem to show a fall in the total alcohol consumed in the last two years, may be incorrect because they are based on conversion factors that are too low.