In full: Jacqui Smith's letter

Thank you for your letter of 1 December regarding the arrest of Damian Green on suspicion of conspiring to commit misconduct in a public office and aiding and abetting, counselling or procuring misconduct in a public office.

I am pleased that you acknowledge the importance of the police being able to conduct an independent investigation impartially and faithfully, but I am disappointed by your apparent suggestion that I should have intervened in operational police matters in this case. I have not sought to intervene in the operational decisions being taken by the police - nor will I do that, and nor should I do that.

Nor will I seek to prejudice the police's investigations in any way. I invite you to state unequivocally that you will do likewise, and that no-one should seek to undermine - in principle or in practice - the operational independence of the police from political intervention.

You claim I have not given a full account of my own knowledge in relation to the arrest of Damian Green MP. That is not the case. I have been absolutely clear that I did not know until after the arrest of Damian Green that he - or any other Member of Parliament - was being investigated by the police or was to be arrested.

You are widely reported in yesterday's media as saying "I think she knew there was an MP involved in this investigation and she decided to simply sit back on her hands." You repeat this claim in your letter as "the only plausible conclusion" that can be drawn from my comments.

This is a mischievous, perverse, inaccurate and wholly unfounded allegation. Furthermore, it runs wilfully and directly counter to the public statements made by myself, the Home Office Permanent Secretary and the Metropolitan Police Service.

As the statement issued by Sir David Normington on 28 November made clear, he was informed by the Metropolitan Police at about 1.45 pm on 27 November that a search was about to be conducted of the home and offices of a member of the Opposition front bench and he was subsequently told that an arrest had been made. This was the first time that anyone in the Home Office was informed that a Member of Parliament was the subject of the police investigation.

I am, of course, prepared to restate all of this on the record in Parliament, and I will be seeking to make a statement at the earliest opportunity. I hope you will make it clear that you accept my account, and that of Sir David Normington, and will now withdraw your claim that we were aware that Damian Green or any other Member of Parliament was under investigation.

You write that I have seen fit to encourage speculation about the true nature of the allegations facing Damian Green. That is not so. The true nature of the allegations he faces is a matter of public record - he was arrested by the police on suspicion of conspiring to commit misconduct in a public office and aiding and abetting, counselling or procuring misconduct in a public office.

Rather than seek to dismiss the offence the police are investigating as "an antiquated common law misconduct offence", you would do better to show respect for the law and the duty of parliamentarians to uphold the law. I ask you to accept that Members of Parliament are not above the law and that the police must investigate if they suspect that an offence may have been committed.

In my interview with Andrew Marr on Sunday, I made the point that the issue facing the Home Office was a systematic series of leaks. Given the sensitive issues that the Home Office deals with - including matters of national security - there was a clear duty to take action to prevent leaks from happening. It would have been negligent to do otherwise.

That principle extends not just to matters of national security or otherwise covered by the Official Secrets Act. It is an important principle of our system of government that no-one should seek to undermine the impartiality and professionalism of the civil service or undermine the operation of the civil service code. To assert that the systematic leaking of government material is not serious if it does not relate to national security, as you and David Cameron have done, is not just a cavalier attitude to take. It is a wholly irresponsible one, and entirely unfit for those who seek to hold high office.

Instead of throwing around unfounded allegations in an irresponsible manner, will you instead commit your party to full co-operation in the police investigation, and disclose all information your party holds