To mark 4/20, a day dedicated to smoking marijuana, we've mapped the world according to cannabis consumption – and the results might surprise you.

The top nation isn't The Netherlands, famous for its coffeeshops, or indeed Portugal, the US or Uruguay, each of which has made strides to decriminalise the drug during modern times. According to the United Nations Office on Drugs and Crime (UNODC), that dubious distinction of biggest marijuana loving nation goes to Iceland.

UNODC data suggests that cannabis is used by 18.3 per cent of Iceland's population (aged 15-64). The US (16.2 per cent) and Nigeria (14.3 per cent) had the second and third highest rates of consumption; while the UK came 26th on the list, followed by Ireland. And the Netherlands? It came 20th.

Data is not available for all of the world's countries - and some figures have been updated more recently than others - meaning caution should be exercised when drawing comparisons.

The 30 biggest weed smoking countries

Iceland - 18.3 per cent of population United States - 16.3% Nigeria - 14.3% Canada - 12.7% Chile - 11.83% France - 11.1% New Zealand - 11% Bermuda - 10.9% Australia - 10.2% Zambia - 9.5% Uruguay - 9.3% Italy - 9.2% Spain - 9.2% Madagascar - 9.1% Czech Republic - 8.9% Israel - 8.88% St Lucia - 8.87% Belize - 8.45% Barbados - 8.3% Netherlands - 8% Greenland - 7.6% Jamaica - 7.21% Denmark - 6.9% Switzerland - 6.7% Egypt - 6.24% UK - 6.2% Ireland - 6% Estonia - 6% Bahamas - 5.54% Sierra Leone - 5.42%

A number of countries have had a rethink on their cannabis laws in recent years.

Portugal decriminalised all drugs in 2001 and within a decade substance abuse was reported to have halved - though that’s not to say the dip in drug taking was directly down to the policy.

Uruguay has adopted a similar approach - it legalised marijuana in 2013 - while California, Massachusetts and Nevada are among the latest US states to vote for its legalisation.

Icelandic residents smoke the most weed, according to a new report

Last year a report claimed legalisation of cannabis in the UK would reduce organised crime, improve the quality (and therefore safety) of cannabis and line the coffers of the Treasury; a legal UK cannabis industry, it calculated, would turn over £6.8 billion annually, with £1 billion going straight to the Treasury.