Mike Penning asks the Government about drug abuse in London

Shadow Health Minister Mike Penning - MP for Hemel Hempstead and polymath - has posed a noteworthy written question to the Government:

"To ask the Secretary of State for Health how many problematic drugs users were estimated to be residing in London in the last year for which figures are available. [240585]

Dawn Primarolo: The estimated number of problem drug users⁽¹⁾ in the London government office region, aged between 15-64, is 74,822. This figure for the latest period available 2006-07.

⁽¹⁾ Problem drug use in this context refers to use of opiates and/or crack cocaine, including those who inject either of these drugs. It does not include the of cocaine in powder from, amphetamine, ecstasy or cannabis, or injecting by people who do not use opiates or cocaine."

Why aren't the abusers of these other drugs included? Is it because their numbers are too hard to calculate or estimate? Is it becase these drugs are considered less problematic? It seems to be a very odd approach.

(Please note that the typo in the minister's answer is not ConservativeHome's.)