Illegal drugs and prostitution will boost the value of the UK economy by around £10 billion, statisticians have revealed.
Both activities are worth 0.7% of GDP, equal to agriculture, accommodation services, such as hotels, or publishing industries, including newspapers and magazines.
European Union (EU) rules mean the Office for National Statistics (ONS) will for the first time have to include illegal activities in its official estimate of the total value of UK goods and services, also known as gross domestic product (GDP).
Based on 2009 prices, the ONS has estimated prostitution will add £5.3 billion to GDP, while drugs will boost the economy by £4.4 billion.
In all the years between 1997 and 2009 the impact ranges from £7 billion to £11 billion, statisticians said.
Campaigners against violence against women said it was "frightening to see such human tragedy financially valued".
A spokeswoman for women's charity Eaves said: "Eaves is surprised and saddened that illegal activities, crime, abuse, suffering and violence would be considered as part of the GDP.
"Given that the entry routes to prostitution and the barriers to exiting prostitution are known to commonly include childhood sexual violence, domestic violence, neglect, abuse, poverty, destitution, coercion and addiction - it is humiliating and frankly frightening to see such human tragedy financially valued and counted as 'productive'.
"It is just one more way in which human lives, women's lives in particular, are devalued, objectified and commodified and another step on the road to the normalisation of pimps as businessmen."
For measuring the contribution of "prostitution services", statisticians will assess the value of rental of brothels, sales of condoms and sales of clothes worn by sex workers.
When assessing the impact of illegal drugs, the ONS will consider production and sales of crack cocaine, powder cocaine, heroin, cannabis, ecstasy and amphetamines.
The data will class growing drugs or importing them as "production", buying them for home use as "expenditure", and selling them as "income".
A number of changes to GDP are expected to add £33 billion, or 2.3%, to the value of the economy.
Crime Prevention Minister Norman Baker said: " The coalition Government is committed to tackling the harm and exploitation associated with illegal drugs and prostitution.
"Our approach to drugs remains clear: we must prevent drug use in our communities and help dependent individuals through treatment and wider recovery support, while ensuring law enforcement protects society by stopping the supply and tackling the organised crime that is associated with the drugs trade.
"There are positive signs our approach is the right one: drug use has fallen to its lowest level since records began and people going into treatment today are more likely to free themselves from dependency than ever before.
"We believe that those who want to leave prostitution should be given every opportunity to find routes out. We will ensure that legislation surrounding prostitution remains effective and continue to work with law enforcement agencies and the voluntary sector to achieve this."