The number of detected crimes of people accessing illegal images of children has gone up by 48% in four years, according to research by BBC News.
Mr Brown added that there was also a decrease in the age of children being abused and that more children were being encouraged to do sexual activities through webcams which were then filmed and uploaded online rather than being groomed to meet up.
"The inhibitions are too few, especially if men are in a room by themselves - it's too easy," he said.
"We need to be asking what is the male psychology that makes them view this imagery? It's not just a few sick men, it's a much larger number.
Donald Findlater from the Lucy Faithfull Foundation, a child protection charity, said the problem was more widespread than police figures show.
"We have to recognise the limited potential of law enforcement to fully deal with this problem," he said. http://www.bbc.co.uk/news/uk-21507006