What happens if you decriminalise drugs?
The Lib Dems and Sir Richard Branson have called on the UK to follow suit of countries like Portugal in treating drugs as a health rather than a criminal problem.
Portgual decriminalised drugs for personal use in 2001, and in the 15 years since has seen a reduction in drug-related crime, deaths and drug use has dropped by half.
Here is what it is currently legal to carry:
The measures have also had an effect on the rate of infections, commonly contracted by intravenous drug use, and crime figures.