Seems like some daft MP handed over a letter on request, rather than saying "out of my gaff, copper, and don't come back till you've got a warrant".
Police 'entered Tory MP's office'
Mr Kawczynski said he felt "eternal shame" over his actions
A Conservative MP has alleged that police entered his Commons office without a search warrant demanding to see constituency correspondence.
Daniel Kawczynski said he found the episode "disgraceful".
The Shrewsbury and Atcham MP said he had handed over a Shrewsbury-postmarked letter related to an inquiry over "white powder" sent to a minister.
But Scotland Yard said a Parliament-based police officer had entered the office "by appointment".
Mr Kawczynski said it was to his "eternal shame" that he had complied by handing over the letter.
His comments follow the arrest of shadow immigration minister Damian Green - and the search of his Commons offices - last year.
Mr Kawczynski said the investigation related to a letter sent to Schools Secretary Ed Balls, which contained white powder that later turned out to be flour.
This had been sent from his constituency, he added.
Mr Kawczynski said he had received a phone call from an assistant telling him that police were searching his office.
Speaking in the House of Commons, he used a point of order to raise the matter, saying: "I am extremely shocked at what I am going to say."
Mr Kawczynski added: "I received a note from my office that there was a police officer in my office demanding to see correspondence.
"They were already present in my office and I went down to see them after making my speech."
The police had been investigating an "important case", the MP said, involving correspondence sent to ministers and had wanted "handwritten samples" of letters received by him.
Mr Kawczynski said: "I was extremely appalled that the officer can behave in this way, to enter a Member of Parliament's office with no warrant and to demand constituency correspondence."
He said he would "have to live with" his decision to hand over the letter demanded by the police.
Mr Kawczynski told deputy Commons Speaker Sir Michael Lord: "After everything that has happened to Mr Green, I find it disgraceful that this is happening and I urge you to investigate."
Fellow Tory MP Tobias Ellwood demanded that Home Secretary Jacqui Smith make a statement to MPs about the matter.
Sir Michael said he understood the "great concern" about the incident but had "no knowledge of this matter".
He told Mr Kawczynski: "If it is as you say it is, then it is obviously extremely serious and my advice would be that you should take the matter up with the House of Commons authorities as quickly as possible."
Sir Michael said he would refer the matter immediately to Speaker Michael Martin.
But a Metropolitan Police spokesman said: "At 1750 this evening an officer based at the Palace of Westminster entered a member's office by appointment concerning a local investigation.
"The investigation was concerning a series of letters received at the House containing non-noxious white powder.
"The officer did not request to search the office and no search was conducted.
"A piece of correspondence matching handwriting of those under investigation was removed from the office after permission was granted by the MP."