Sian Berry, the Green Party candidate for Mayor, has called for the legalisation of drugs and prostitution.

Unveiling the party’s election manifesto for May's Local and Mayoral votes, she said harm was caused in prostitution "because of illegality. It's the same with drugs."

She wants to tax the £8billion drug trade, taking the money away from the criminals and bring in £2bn for public services.

Cannabis would be sold in Amsterdam style cafes and hard drugs like heroin would be available on prescription. New Zealand operates a similar system.

Green Party drugs spokesman said:

"Current policy is not working. There needs to be a radical change with regulation and control which would lead to a massive reduction in crime."

Livingstone to benefit?

The controversial polices may inadvertently help embattled Ken Livingstone’s campaign.

The fourth placed candidate for London Mayor had previously called on her supporters to second Livingstone on their ballot paper. Meaning her votes would become his votes if she, as expects falls out of the race.

Ken Livingstone said his second preference vote would be going to Green candidate Sian Berry at the launch of their "Common Green Agenda" this morning.

In every London Mayoral election so far second preferences decided the outcome.