[sangnoir]

Parliament is not into enforcing laws - it writes them. Parliamentary sovereignty means it can publish internal documents[1] if they decide it's in the public interest, if not, the MP will be appropriately censured by their peers.

1. In the US, the president (executive) can declassify any classified information, the DOJ or judiciary may publicize (discovered) internal documents for trials/indictments before guilt is established (note: IANAL). In the UK, Parliament is supreme to the executive and judiciary.

[rlucas]

In the US, Congress enjoys the Speech and Debate privilege, meaning pretty much the same. It's even in our (written, unlike the UK) Constitution.