More than 23,000 police officers and staff are moonlighting in second jobs, it has been reported.
According to the Mail on Sunday, more than one in 10 officers in England and Wales now take on extra work.
This was found to include selling ice cream, undertaking, giving skiing lessons, holding seances and pole dancing.
Police staff are allowed to take second jobs or run companies if approved by their superiors.
Unless there is a direct conflict of interest, permission is usually given.
Figures from Her Majesty's Inspectorate of Constabulary showed at least 23,043 police staff had second jobs out of a workforce of 201,575 in May 2012.
That was up 19% from March 2011 when 19,329 had second jobs.
The number of investigations into second jobs soared in the nine months to May, with 154 reviews carried out - more than 17 a month.
In the previous year, there were 82 - fewer than seven a month.
Those investigations led to 10 officers either being sacked or resigning, while 65 warnings were given.
A Home Office spokesman said: "It is the responsibility of chief constables to ensure that any secondary jobs held by officers do not harm the public's perception of the police or result in any conflict of interest.
"The Home Secretary will put new proposals ensuring the highest standards of integrity in the police to Parliament in the New Year."
The news came as a senior Labour backbencher warned public confidence in the police has been shaken due to a "dangerous cocktail" including the 'plebgate' affair and the results of the Hillsborough Inquiry.
Keith Vaz, chair of the Home Affairs Select Committee, which will begin an inquiry into police accountability, integrity, internal corruption and malpractice next month, said it is a "defining moment" for the service.
He urged Prime Minister David Cameron to host annual summits with senior officers and called for "a new Magna Carta" for policing.
Writing in the Sunday Express, Mr Vaz also criticised Home Secretary Theresa May for trying to enforce radical changes without having a proper dialogue with officers.
He acknowledged existing police structures needed to be reformed but said Mrs May's changes were "too rapid and too far-reaching".