The BBC has the story of the police’s arrival at Daniel Kawczynski MP’s Commons office.

Thursday update: The Speaker has rebuked Mr Kawczynski over the matter – BBC report here. And Daniel Kawczyndki has now issued the following statement:

"I welcome the Speaker’s statement to the House in response to my complaint that the police had entered my office without consulting me and threatened to seize potentially confidential constituency correspondence from a young member of my staff and a student intern.

"I wish to make it clear that I fully support the police in all their efforts to keep Members of Parliament, their staff and the public safe and secure.  Indeed, had the police approached me personally and explained the circumstances of their investigation, I would have cooperated fully, while obviously ensuring there was no unjustified breach of the duty of confidentiality I owe to my constituents.  It goes without saying that if they had not been sure, as they already were in this case, that the substance was not harmful, then protecting public safety would be paramount and I would have made no objection to their actions.

"I do hope, however, that the police will reflect on their actions in this case and learn important lessons:  Telephoning an intern to ask if they could come around immediately to show my staff some handwriting samples does not constitute making an appointment with me; stating to junior staff in my absence that if correspondence was not provided voluntarily, they had the power to seize it, was also unacceptable.  It was also absolutely clear from the televisions all around Parliament that I was not only in the Chamber at the time but actually making a speech on pensioners and their savings.

"I welcome the Speaker’s ruling that from now on if a Police Officer wishes to enter the office of an MP and to try to secure any documentation he or she will first of all need to inform the Serjeant at Arms and the MP in question. This is important as it will allow the MP and the Commons authorities to make appropriate time to sit down properly with the police and see how best they are able to assist them with their enquiries while properly considering the rights of their constituents."