WikiLeaks founder Julian Assange was bitterly criticised by a fellow freedom of information campaigner on Friday night.
Heather Brooke said of the man who used the website to release thousands of secret documents: "I can not think of a more crazed and irrational person.
"He could have changed the whole way we look at government secrecy.
"Tragically he threw that opportunity away."
She was referring to the Afghanistan war logs which Mr Assange insisted on releasing on WikiLeaks without withholding the name of people who became Taliban targets as a result of publication.
"Assange did not respect his sources, which every journalist knows you should," said Heather Brooke.
"He was seduced by power and anyone who challenged him in WikiLeaks was summarily dismissed."
We need transparency in government, the security services, police and military, but "transparency also requires responsibility", she told the audience.
Heather Brooke respected her sources when someone within the Houses of Parliament offered a computer disk of MPs' expenses claims to the press.
This followed her five-year campaign to have details of how MPs spent public money made public.
The resulting scandal was one reason why Wells MP David Heathcoat-Amory lost his seat in the 2010 General Election.
As an American-trained journalist Heather Brooke was amazed how much secrecy surrounded politics in Britain, unlike the USA.
But the digital revolution, in particular the internet, now made checking on those in power much easier because it allowed huge numbers of ordinary people in different places to connect at great speed and form groups.
Freedom of information requests can be made by citizens of authority bodies and such information put on the web.
People in power liked to keep inconvenient facts to themselves and felt that the public could not be trusted.
Information is power "and decisions to restrict information should be challenged," said Heather Brooke.
"We need an Official Disclosure Act so people can be punished for withholding information."