There's a saying in the United States: Sunshine is the best disinfectant. What they mean by that is when you shine a light on the misdeeds of others, they are most likely going to start behaving in a more acceptable manner. It seems to me that Parliament's attempt to keep The Guardian from reporting on its actions is the sort of thing people who know they're misbehaving might do. It's shady, it's unethical, and it needs to be prevented.
I'd like to ask the English people a question. Still think your free? Still think you've got rights? I'm not sure. If the Parliament can silence a newspaper then it should be easy enough to shut you up. As an English person you are not the inheritor of freedom and democracy the way I am as an American. You can change that though. Fight for a constitution with a bill of rights. Freedom of Speech, No established Religion and total freedom of Religion with non-interference from the government, and the Right of individual citizens to keep and carry guns.
No, Parliament's right to keep The Guardian from reporting on its procedures is not ethical, because it is most important that people have the right to free exchange of information. The government should error on the side of allowing people to know its procedures. They should not shut down The Guardian unless they have a reason to.
Governing bodies are supposed to not control the media or shut it out. Some countries in 1st world status defy this such as China that has their hand on everything printed, but that doesn't make any efforts to censor or stifle what the media is trying to do ethical. The people have the right to know what is going on.
What does Parliament have to hide? The British government should be as open as possible when it comes to using taxpayer money. Yes, things such as national security should be discussed behind closed doors. However, the press has the right to keep tabs on Big Brother even though there isn't as much "freedom of the press" in Great Britain as in the United States.
Parliament's right to keep "The Guardian" from reporting on its procedures is not ethical. They do not have a freedom of the press like we do in the US, however, I still think it is unethical to silence the newspaper like that. They should be allowed to publish anything that they want to.