The Freedom of Information Act risks forcing ministers and civil servants into a system of "oral government" in which important discussions are never written down, the former Cabinet Secretary Lord O'Donnell has warned.
The peer, who left his role as head of the Civil Service in December, said the fear of minutes eventually being published was "driving stuff underground or into non-FOI-able routes".
In an interview with BBC Radio 4's The Westminster Hour, Lord O'Donnell said the process would result in "worse public policy decisions". He repeated his call for the Act to be overhauled.
"You just don't know when you write something down whether that is eventually going to be decided by a tribunal of people who may have never worked in government whether or not that should be released," he said.
"If everybody thinks, well, that's all going to become public and that's going to be used against me, people will naturally say, OK, well perhaps I had just better keep quiet. And then you get to a situation where you have oral government."
Lord O'Donnell said a similar issue in the US led to the use of Post-it notes during discussions.
"They'd stick 'I disagree with this' on them. And then there were Freedom of Information requests for the Post-its," he said.