Criminals are making millions of pounds a year by selling personal details of unsuspecting victims, the Information Commissioner said today.
Christopher Graham said the "modern scourge" of selling personal information illegally was "hugely profitable" and greater sanctions were needed to tackle it.
In one case, employees were selling customers' details to a rival firm and raking in £70,000 a year as part of an illegal trade that generates millions of pounds a year, he said.
The Government and authorities need to make clear that such offences "are not just the equivalent of pinching the office stationery, a crime against the boss", he said.
"These are crimes against citizens that need to be properly prosecuted with a real deterrent penalty.
"We've found that the very limited fines in magistrates courts doesn't do the trick."
Instead of the current fine of up to £5,000 if offenders are convicted by magistrates, tougher sanctions, including up to two years in jail, should be brought in, Mr Graham said.
"The trade in unlawful personal information is hugely profitable," he said.
"Very recently the Government has woken up to the fact that this is a modern scourge.
"It's about dodgy private investigators, child custody battles and nasty matrimonial disputes and the lack of a serious penalty is a real problem."
Asked by Keith Vaz, chairman of the Commons Home Affairs Select Committee, if the illegal profits involved ran in to the millions, Mr Graham said: "Yes."