In a paper in which it estimated prostitutes' "sales" and costs incurred -- condoms and "working clothes"-- the Office of National Statistics (ONS) said the inclusion of such activities was part of a raft of improvements to the way the economy will be measured from September.
The adjustments bring Britain's estimates of Gross Domestic Product -- or national economic output -- more into line with other European countries, where some activities such as prostitution or the trade in certain drugs are not illegal.
Prostitution itself is not illegal in Britain, but activities surrounding the trade, such as keeping a brothel, are, prompting critics for an overhaul of what they see as muddled rules.
Similarly, calls have mounted in Britain for the partial legalisation of some drugs, both to curb the crime associated with prohibition and also to boost tax revenues as the government tries to plug a big budget deficit.
"As economies develop and evolve, so do the statistics we use to measure them," ONS Chief Economic Adviser Joe Grice said in a statement.
Statisticians estimated that there are 58,000 prostitutes in the country seeing up to 30 clients a week each, and assumed that the only drug produced in Britain is cannabis.
Other drugs included in their calculations were crack cocaine, powder cocaine, heroin, ecstasy and amphetamines.
Overall, adjustments to the way Britain's national accounts are reviewed, including measures such as looking at revenues from non-profit institutions, would have boosted 2009 GDP by between four and five per cent.