CPS Research Fellow Kathy Gyngell joined journalist Peter Hitchens in giving evidence against drug decriminalisation to the Home Affairs Select Committee.
"It is also hearing from witnesses opposed to any relaxation of the laws on drug use - journalist Peter Hitchens, Kathy Gyngell from the Centre for Policy Studies and Mary Brett from 'Cannabis Skunk Sense', which seeks to draw attention to the risks posed by cannabis.
Hitchens said the government had "abandoned many years ago" attempts to prohibit the use and possession of cannabis and some Class A drugs - claiming there was a "de facto decriminalisation".
He said that drug use was "wrong" and the law should clearly state this.
Ms Gyngell said cocaine use was only "common in certain circles" and that if decriminalised, the rate of usage would rise sharply.
The committee has previously taken evidence from medical professionals involved in drug treatment and drug education."
The session made headlines as actor and comedian Russell Brand gave evidence in favour of decriminalisation. Although taking a different view from Gyngell to the legal status of drugs, there was some common ground as Brand highlighted the mistake of methadone treatment and called for an 'abstinence'-led approach, something highlighted by Kathy in the CPS pamphlet 'Breaking the Habit'.
To read the full article, visit the BBC News web page.