BBC Click has admitted paying cybercrooks thousands of dollars to buy access to a botnet as part of a controversial cybercrime investigation, broadcast over the weekend.
In a website story accompanying the heavily-promoted report, BBC Click reporter Spencer Kelly explains how licence fee payers' money was used to buy access to virus-infected machines under the control of hackers in Russia and the Ukraine.
After months of investigation and a few thousand dollars, we had managed to buy a botnet from hackers in Russia and the Ukraine.
The process began in chatrooms where hackers advertise their services. You have to earn their confidence, then negotiations take place in instant messaging applications.