Lord Kerslake, the former head of the Civil Service, has praised the "fundamental" importance of the Freedom of Information Act.
Speaking before an independent cross-party review of FoI chaired by Labour deputy leader Tom Watson, he told how the act "tips the balance towards openness" in the Civil Service.
He said: "I do feel feel very passionate about this. I think it's not just the individual cases… it has shifted the culture, I've lost count of the number of times I was in conversation about whether we should publish something or not, and people said: 'Well, we might as well publish it because it's going to be FoI-able.'
"It tips the balance towards openness and that is absolutely fundamental."
He added: "We have, in my view, a yawning gap between the governing and the governed in this country…
"The only way that we can restore that trust is to become more accountable, not less. Anything which seems to restrict that accountability is, in my view, a false move."
Kerslake dismissed the suggestion FoI has a "chilling effect", saying this must be happening in people's "own heads". Among those to have suggested a "chilling effect" is Kerslake's successor, Sir Jeremy Heywood.
He also accused ministers of "double standards" in seeking to restrict FoI laws while routinely leaking official information when it suits them.
"If people are experiencing a chilling effect it's largely in their own heads, not in the reality. The act is now a mature piece of legislation with perfectly predictable outcomes," Kerslake (pictured above, from UK Civil Service video) said.
"The far greater challenge is the fact that information is routinely leaked by special advisers and ministers.
"There is a double standard going on here we should just acknowledge. The public see that and that information is controlled."
Kerslake also criticised the composition of the Government-appointed commission set up to review the FoI Act, saying that it was largely made up of people who had spent their lives "defending institutions, not challenging them".
There are widespread concerns that the Government's Independent Commission on Freedom of Information will suggest the introduction of FoI charges, further protection for internal dicussions and strengthened ministerial veto.
Kerslake contrasted the role played by Information Commissioner Christopher Graham in promoting access to official information with the FoI commission, which is chaired by a former Treasury mandarin and includes two former home secretaries, Jack Straw and Lord Howard of Lympne.
"I think Christopher Graham has done an effective job in his role. It's no coincidence that he is a former journalist very unlike the commission which seems to be populated by people who have spent their lives defending institutions, not challenging them," he said.
Also appearing before the meeting in Parliament yesterday was TaxPayers' Alliance chief executive Jonathan Isaby, Liberty director Shami Chakrabarti and Maurice Frankel, director of the Campaign for Freedom of Information.
All defended the act, and suggested ways it could be improved, such as bringing charities and private companies that perform public sector jobs under FoI.
Isaby said: "The cost of FoI would be far cheaper if all this stuff was just published automatically and you didn't have to go through the process of asking for it in the first place.
"We've already paid for it to be done… So much more information should just be published online very, very, very cheaply indeed as a matter of course so it's just there, so costs can be kept down."