And here's the full response from Andy Coulson's lawyers to the Home Affairs Committee chairman:
"We act for Andy Coulson who has passed us a copy of your letter to him of 6 July 2011.
We, of course, understand that your Committee would wish to have answers to the questions you pose, particularly as the issue of phone hacking has taken a new turn in the past 48 hours and there is intense media interest in it.
Your Committee was convened shortly before the first police investigation into phone hacking concluded, and just before the CPS advised on the evidence that has been collected. Since then, however, the current police investigation into allegations of phone hacking has commenced (Operation Weeting), led by Deputy Assistant Commissioner Sue Akers, and on Wednesday 6th July a further police investigation (Operation Elveden) was announced to look into new allegations about payments by the News of the World to police officers. This is also being led by DAC Akers. In fact, by the time you receive this letter Mr Coulson will have attended a police station in London voluntarily to be interviewed.
These allegation, individually and collectively, are extremely serious. A number of direct allegations have been made in the media about Mr Coulson's role in the subject matter of both Metropolitan police inquiries. Because of this, we have advised Mr Coulson that it would be inappropriate to respond to the questions posed in your letter, as they go to the very heart of the issues that the police investigations are looking into. We recognise it is within the prerogative of a parliamentary committee to investigate these matters but it must be important to balance the interests of Parliament against the interests of justice in ensuring that any criminal investigation or process is not prejudiced by a parliamentary inquiry prematurely exploring issues with potential witnesses or suspects before the police have had a chance to complete their inquiries. Of course a claim of parliamentary privilege might be an answer to any concerns that the courts might have about any interference by a Select Committee with the course of justice but we must ask you to reflect on whether it is appropriate for you to pursue the inquiries you make of Mr Coulson at this time.
You will find the answers to some of your questions in Mr Coulson’s previous evidence as he has already been questioned in Parliament by the Culture, Media and Sport Select Committee.
There has been much debate about the police investigations proceeding before any public inquiry is commenced, so as not to prejudice those investigations. We would respectfully submit that the same consideration should apply equally to the Select Committees, particularly where they are asking questions of an individual who is in jeopardy of criminal investigation and possible criminal proceedings. To do so would flout the enshrined statutory and common law rights and protections he ordinarily has, in every environment other than a Parliamentary one."