Home Department written question – answered on 4th April 2011.

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Photo of Charles Walker Charles Walker Conservative, Broxbourne

To ask the Secretary of State for the Home Department what the average THC content of seized skunk cannabis was in the latest period for which figures are available; what the average THC content of cannabis seizures was (a) five, (b) 10 and (c) 20 years ago; and if she will make a statement.

Photo of James Brokenshire James Brokenshire Parliamentary Under-Secretary (Home Office)

The latest data from the Forensic Science Service Ltd (FSS) show that the average tetrahydrocannabinol (THC) content of mature flowering tops from plants, otherwise known as sinsemilla, seized and submitted to the FSS from the 1 January 2008 to the present day was 14.0%. By comparison, during the same period, the average THC content of traditional imported cannabis and cannabis resin was 12.5% and 5.5% respectively.

Information on average THC levels of cannabis available in the UK prior to 2008 is available in the Advisory Council on the Misuse of Drugs 2008 report 'Cannabis: Classification and Public Health', which can be found on the Home Office website via the following link:

This summarises data available at that time, including FSS data from 1995 to 2007 and data from the Home Office's Cannabis Potency Study 2008, published by the Home Office Scientific Development Branch. Information on average THC levels of cannabis prior to 1995 is not available.

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Harry McCulla
Posted on 5 Apr 2011 9:24 pm (Report this annotation)

It is interesting that the average THC levels of cannabis prior to 1995 are not known, since this means that any comparisons between cannabis strengths today and those of the 1960s and 1970s are meaningless.