Rebekah Brooks has been released on police bail until October following her arrest by appointment at midday on Sunday.
We should of course always remember that an arrest does not in itself mean someone has done anything wrong, but rather allows investigators to question people under the provisions of the Police and Criminal Evidence Act 1984, but whatever the substance or lack of it, this will undoubtedly have implications for John Whittingdale's Culture, Media and Sport Inquiry.
So how will developments affect Tuesday's Session? Strictly speaking, MPs could still insist she appear, but Parliament could of course decide it would be wrong to ask Mrs Brooks to appear under the circumstances. Certainly they would regret missing out on quizzing all three players in the phone hacking saga at this early opportunity.
Now, it had been expected that Brooks and the two Murdochs would attempt to stonewall MPs, refusing to answer tricky questions on the grounds of an ongoing criminal inquiry - but well placed sources tell me that legal advisers to the CMS Committee were certain that all three could be compelled to answer since neither one of them had been arrested.
But the landscape has changed, and Brooks' arrest affords her strong protection in law. CMS Committee Clerks are now studying Parliament's Sub Judice Rules and advising the Committee - similarly, it seems certain that Lawyers for Mrs. Brooks will be consulting the law-books also and advising her on which questions, if any, she would have to answer if she attends.
There is no way of being certain what Parliament's decision will be - and it really could go either way, but my feeling is that Parliament will postpone her session so not to be seen to be prejudicing any criminal case - and given that the alternative would be a boring "no comment" spell.
And so finally, one must look at the timing of today's arrest. It is frankly staggering that Officers have chosen today to act, since they would surely know that Parliament will almost certainly be impeded as a result. Some suspicious folk might even see it as a swing at Parliament given last week's uncomfortable Evidence by serving and former senior Met Officers.
Of course, I couldn't possibly comment.
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