This is how much money Sheffield Council made selling voters' data
Sheffield Council made more than £13,500 selling data from the electoral roll in the past two years.
The local authority sold the information - including names and addresses - to groups including political campaigns, credit score companies, the blue badge service as well as mapping specialists.
It was revealed in a Freedom of Information Act request but earlier records for the authority were not recorded.
However, Doncaster and Barnsley metropolitan borough councils made £8,877 and £11,331.50 respectively in the past five years.
Sheffield Council said all the money it made from selling data goes towards planning and running elections.
Councils in England and Wales are required to have an electoral registration officer responsible for keeping the information up to date but who works independently from the council.
By law, the electoral registration officer has to sell the data to certain agencies and at rates set by the government.
But a number of organisations including the Local Government Association and Big Brother Watch called for an end to the practice, warning that some unscrupulous firms could be abusing the system for publicity.
Silkie Carlo, director of Big Brother Watch, said: "No public authority should sell residents' personal information to private entities for profit.
“This sale of data leaves us open to targeted advertising and undermines trust in councils.
"The open register should be opt in rather than opt out - that way, we could truly see how many people want their data sold for marketing purposes."