Google has been found advertising and profiting from illegal products and services through its automated AdWords programme.
A BBC investigation found Google's AdWords advertised links to unofficial London 2012 Olympics ticket resellers, as well as sites selling cannabis and fake ID cards.
The BBC said Google plans to keep the revenue it makes from advertising illegal services, even if they have to be taken down following police requests.
Google told V3 that it has already taken down some of the "violating Olymics ads".
The BBC investigation was launched after illegal Olympic tickets were found at the top of Google searches and members of the UK public were fooled into buying tickets that did not exist.
The London Olympic Games and Paralympic Games Act makes it illegal to sell tickets to the Olympics without authorisation from the London Organising Committee
Google's AdWords programme is partly automated, but keywords on adverts are filtered to protect customers from illegal products and services.
"We have a set of policies covering which ads can and cannot show on Google. These policies and guidelines are enforced by both automated systems and human beings," Google said in a statement to V3.
"When we are informed of ads which break our policies, we investigate and remove them if appropriate."
Google encountered similar problems with its AdWords programme in August when US web users were subjected to adverts for illegal drugs from Canadian pharmacies.
Google was fined $500m and admitted it should not have run the adverts.
Google AdWords is the firm's main source of revenue.
Geoengineering on the sea floor near glaciers would form a new ice shelf to prevent melting
Alterations in capillary blood flow can be caused by body position change
Curiosity rover is in 'normal mode' but not transmitting scientific data back to base
NatWest outage comes a day after Barclays' IT systems shut out customers and staff