Cannabis: Commons committee to be investiagted
In its first major inquiry of the new parliament, the powerful home affairs committee will also question whether current drug rules work.
Witnesses include key government figures such as the Lord Chancellor. Lord Irvine of Lairg. and Home Secretary David Blunkett.
It comes against a growing background of opposition to the banning of marijuana from politicians of all sides and national newspapers.
The committee will look at the effect of liberalisation on the availability and demand for drugs.
It will also study the effect of relaxing restrictions on drug-related deaths and crime.
Practical
The committee, which will meet in October, will also examine whether decriminalisation is desirable and if not, discuss "practical alternatives".
The move comes amid growing backbench calls, including from former Tory Cabinet minister Peter Lilley, for the liberalisation of laws on marijuana.
The new committee will look at the effectiveness of the 10 year national strategy on drug misuse and take into account the Police Foundation's report on drugs which was chaired by Dame Ruth Runciman.
The issue arose earlier this month when former Tory deputy leader Peter Lilley rocked die-hard traditionalists in the Conservative party with his call to legalise cannabis.
Mr Lilley envisaged magistrates issuing licences for outlets selling cannabis to over-18s. Downing Street has firmly resisted any liberalisation of the drugs laws, although Mr Blunkett has said there should be an "adult, intelligent" debate on the issue.
Impetus
Leading charity DrugScope welcomed the inquiry as a valuable contribution to a more open and mature debate on drugs in the UK.
DrugScope director of communications Harry Shapiro said: "Last year's Police Foundation Inquiry gave the drugs debate a much-needed impetus.
"We have seen evidence in recent weeks that more politicians are ready to take on this complex issue and explore the possibilities for change.
"It is a subject which interests a large number of ordinary people and an open and mature debate could help re-engage many, particularly the young, in the political process."
Last week, the overwhelming majority of 116 Labour MPs taking part in a poll for the BBC World at One programme supported a substantial inquiry into the drug, such as a royal commission.