I think as the Speaker himself indicates in his report on this occasion and on the decision of last April pertaining to Afghan detainees, Parliament has the right to receive whatever information it requests from the government as part of its constitutional function of holding the government to account.
However, let's not forget, it's always open to the government to say, “No, you're not going to get it”, for whatever reason. And then it takes its chances with the House, because the House may not be happy with that, and it's up to the House to decide what it's going to do about that.
So I'm not saying that the government can never say no. I'm just saying that if they say no, the onus is on them to justify why they're saying no, because the basic principle is that the House should receive whatever information it seeks for it to do its function in holding the government to account or, as you mentioned, in reviewing legislation.