Sure. This has been a topic that has been heavily analyzed in the United States. The Whistleblower Protection Enhancement Act of 2012, which was passed after 13 years of study, has four of what we call anti-gag provisions in the law.
The principle is essential because otherwise agency secrecy agreements can cancel out the statutory free speech rights, or settlements can make a joke of the quest for justice by sacrificing the public interest. There has to be a responsible balance.
The boundaries in the United States are that if information is marked as classified for military reasons, or it's release is specifically prohibited by a statutory provision, by our Congress or your Parliament, you can't publicly release that information. Any other restrictions, however, are superseded, if the information is covered by the whistle-blower law. If it's evidence of illegality or threats to public health or safety or mismanagement, you don't have the free speech right to make a blanket disclosure. However, that particular part of the information, you cannot be gagged from. That's been in every U.S. whistle-blower law since 2000 because without it the laws would be circumvented easily.