Charles Clarke, the Labour Party chairman, condemned the "antediluvian" procedures for vetting books by former security service staff yesterday.
Mr Clarke called for reform as he intervened in the controversy about a new book by Stella Rimington, the former head of MI5.
At the weekend Dame Stella called for reform of the Official Secrets Act, in advance of the serialisation of her memoirs in a national newspaper.
The Home Office made clear that ministers felt "regret and discontent with the decision to publish".
But Mr Clarke criticised the complex vetting procedure. He said: "I do think the process of vetting these kinds of things is very defensive, unnecessarily defensive, and damages the public welfare in this country."
Mr Clarke referred to the experiences of his father, Sir Richard Clarke, a former permanent secretary at the Ministry of Technology, who experienced the vetting procedure at first hand after he left the Civil Service.
Mr Clarke told the BBC1 Breakfast with Frost programme: "I think our current process for vetting these types of things is antediluvian. They compare badly with the American process.
"We want to have a fair and open approach to it. I don't think you should ... and I don't think Stella Rimington thinks [you should], reveal details that affect national security and they obviously have to be protected. But the line between national security on the one hand and informed public debate about the way the public sector goes about taking its decisions, is a difficult one."
The book reopened the debate about the 1911 Official Secrets Act after Dame Stella called for the legislation to be reformed to allow former secret service agents to write about their experiences.
Civil liberties groups have used the book's publication to renew calls for repeal of the Act.
Mr Clarke, a former home office minister, said he had not yet read Dame Stella's book, but indicated that it did not breach national security.
He said: "I feel very much in two minds about this one. If I felt that Stella Rimington's book was threatening national security I would be very concerned about it."Reuse content