Senior MPs say Britain is losing its war on drugs and needs to consider legalisation, according to news reports.
Members of the powerful Home Affairs Committee are set to tell Prime Minister David Cameron that the current approach has failed and new strategies are required.
Pressure on the PM is expected to include the setting up of a Royal Commission into redrafting of drug laws.
According to the Mail on Sunday, the MPs concluded that prison sentences have failed to reduce drug dealing.
The MPs also believe the drug black market is aided by stringent regulations.
Many in the Conservative Party oppose drug law reform, however some coalition colleagues in the Liberal Democrats have recently backed reform.
An unnamed MP on the committee told the Mail on Sunday that the current laws are "unfit for purpose".
Existing legislation was slammed as being a relic of the 1960s and not suitable to cover the current myriad of circumstances involving drugs.
The former Government drugs adviser, Professor David Nutt, told Sky News that a shift in the international position, centred on the United Nation's policy, is also needed.
He said: "We need to review the misuse of drugs act which is 40 years old and is completely out of date in terms of the drugs that are in it.
"The conventions on drugs are probably causing more harm than good in terms of the international global position."
Politicians have been urged to look at Portugal, which has altered its legislation.
The Home Affairs report comes just days after a shift occurred in the United States to drug possession.
Washington state has become the first state in the US to legalise marijuana, with Colorado set to follow suit.
A number of other countries have also sought to approach the issue of drugs from other than a law enforcement perspective.