If, as it seems, the police failed to point out to the House of Commons serjeant at arms, when they applied for permission to search a parliamentary office, that she had the right to refuse consent and demand a warrant, they broke the law.
But neither the new serjeant at arms, Jill Pay, who gave permission, nor the speaker, Michael Martin, whom she telephoned about it, thought to ask.
Murdoch and his son James appeared at the committee after the deputy serjeant at arms was sent to deliver formal summonses in person.
In a Commons statement to explain why the Metropolitan police were allowed to search the shadow immigration minister's parliamentary office, Martin revealed: The Metropolitan police informed Jill Pay, the serjeant at arms, last Wednesday that the arrest of an MP was being contemplated.
The Commons serjeant at arms has power to detain members of the public who disrupt proceedings until the end of the day's sitting, though these individuals are not usually charged with contempt.
Martin is expected to reveal whether he personally authorised police to enter the palace, and what role was played by the serjeant at arms, Jill Pay, and the clerk of the Commons, Malcolm Jack.
The common serjeant of London, Richard Marks QC, remanded him in custody until sentencing on 28 April.
It is my belief that the serjeant took advice from the clerk of the house regarding the request to search, he says.
On the arrest of Green, he says the "poor serjeant at arms had it all dumped on her shoulders".
She has worked at Westminster since 1994, firstly as head office keeper and then, from 2004, assistant serjeant at arms.
