Figures released following a question to City Hall by Assembly Member Murad Qureshi last week show a steady annual rise in recorded crime, from 465 in 2002-2003 to 2,375 in 2011-2012.
The Metropolitan Police has been responsible for tackling park crime since 2003-2004.
Mr Qureshi said: “When the Royal Parks were managing there appears to be less crime; since the Met takes over there is more. It does suggest the Parks have been less of a priority.”
Mr Qureshi, who is a jogger in Regent’s Park, said he asked the questions following reports of a day-time rape of a young woman in May.
Explaining the rise, Mr Johnson said: “An increase in the number of crimes is attributed mainly to pro-active park policing approach especially to drug-related offences.
"A breakdown of the crimes shows an increase in drug offences due to pro-active policing so that the parks are not seen as a “˜free drug-taking/dealing zone’.”
Data for 2003-2004 had gone missing and figures could not be provided for that year.
Mr Qureshi, said he has written to the commissioner about the figures, added: “How has policing the Royal Parks been undertaken?
"I would like to know how the parks are policed operationally, for example, are they part of the Safer Neighbourhoods policing remit or is there a special dedicated unit?”
Mr Johnson said that a “dedicated Royal Parks Operational Command Unit” was set up on April 1 2004 by the Met, adding: “The unit provides 24/7, high visibility policing and public reassurance, in line with the principles of safer neighbourhood policing.
"It also tackles crime, disorder and anti-social behaviour, enforces Royal Park regulations and deals with local priorities.”
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