Illegal drugs and prostitution contribute around 10 billion pounds a year or nearly one per cent to Britain's economy, according to the first official estimate of the shadowy activities in the country.
Illegal drugs and prostitution boosted the UK economy by 9.7 billion pounds - equal to 0.7 per cent of gross domestic product - in 2009, according to the first official estimate by the Office for National Statistics (ONS).
More than half of the 10 billion pounds - 5.3 billion - is attributable to prostitution while illegal drugs are worth 4.4 billion pounds, the ONS said.
"For the first time official statisticians are measuring the value to the UK economy of sex work and drug dealing - and they have discovered these unsavoury hidden-economy trades make roughly the same contribution as farming - and only slightly less than book and newspaper publishers added together," The Guardian reported today.
Other illegal activities, such a the smuggling of alcohol and tobacco, are already included in GDP and make up some 300 million pounds.
The inclusion of illegal drugs and prostitution is part of radical changes being made to European Union regulations on calculating the Gross Domestic Product.
According to the estimates there were 60,879 prostitutes in the UK in 2009, who had an average of 25 clients per week - each paying on average 67.16 pounds per visit.
The statisticians say there were 2.2 million cannabis users in the UK in 2009, consuming weed worth more than 1.2 billion pounds. They calculate that half of that was home- grown - costing 154 million pounds in heat, light and "raw materials" to produce.
"In terms of the new concepts coming in, illegal activities is the biggest," said Graeme Walker, head of national accounts at the ONS.
"For the rest of GDP we do things like sending questionnaires to businesses, asking them how much they have earned.
"We don't think it would be right to directly collect information on [illegal drugs and prostitution] and we have no plans to contact people involved in these activities.
"We think our data fits the purpose for giving people an idea of the size of illegal activity," The Telegraph quoted Walker as saying.
The more inclusive approach brings the ONS into line with European Union rules, and will eventually allow comparisons of the size of the shadow economy in different member states.
