• Defence secretary steps down over links to controversial unofficial adviser Adam Werrity • How the Guardian broke the story 4.32pm: Here is the full text of David Cameron’s letter to Liam Fox. Like Fox, Cameron (left) focuses on his work as defence secretary, especially in Libya and in reforming the finances of the Ministry of Defence. Dear Liam, Thank you for your letter. I understand your reasons for deciding to resign as defence secretary, although I am very sorry to see you go. We have worked closely for these last six years, and you have been a key member of my team throughout that time. You have done a superb job in the 17 months since the election, and as shadow defence secretary before that. You have overseen fundamental changes in the Ministry of Defence and in our armed forces, which will ensure that they are fully equipped to meet the challenges of the modern era. On Libya, you played a key role in the campaign to stop people being massacred by the Gaddafi regime and instead win their freedom. You can be proud of the difference you have made in your time in office, and in helping our party to return to government. I appreciate your commitment to the work of this government, particularly highlighting the need to tackle the deficit, and the relationship between Britain’s economic strength and our national security. You and Jesme have always been good friends, and I have truly valued your support over the years. I will continue to do so in the future. Yours ever, David. Jesme is Fox’s wife, Jesme Baird. 4.23pm: The resignation letter goes into very little detail about his links with Adam Werrity or the allegation that he was in effect running a shadow foreign policy regarding Sri Lanka . He says only that he “mistakenly” allowed the distinction between “my personal interest and my government activities” to become blurred, and that the “consequences” of this have become clearer. David Cameron has said he is very sorry Fox has resigned but “I understand your reasons”. Fox’s was a tricky case to handle for Cameron. The prime minister will not have wanted to alienate his own right wing by being seen to abandon one of their most high-profile standard bearers. Fox was a leadership rival of Cameron’s in 2005 and may have seen himself as a replacement for Cameron one day. In that sense he may be more dangerous for Cameron on the backbenches, where he may become a focus for internal Tory opposition to the prime minister. My colleague Allegra Stratton has written about Fox’s resignation here . She points out that Fox is the first Tory to be forced out of the coalition, and the resignation will trigger the prime minister’s first reshuffle, “an operation he had wanted to hold out doing until half way through the parliament”. It is expected Cameron will perform a limited reshuffle, Allegra writes, merely replacing Fox without going reorganising his entire government line-up. Fox is said to have crumpled under the weight of this week’s revelations and the prospect of another weekend of speculation He could not hold out until the inquiry into his behaviour wound up officially – expected to be at some point next week. The prime minister had always held out the right to exercise his own judgment and keep Fox in his post even if O’Donnell’s report had been critical, but the defence secretary decided to short-circuit the process and limit the personal and political damage. It is understood that Werritty’s appearance before Sir Gus O’Donnell – the man performing the inquiry to establish the propriety of his work – did not impress the cabinet secretary. 4.21pm: Here is Liam Fox’s letter of resignation to the prime minister in full: Dear David, As you know, I have always placed a great deal of importance on accountability and responsibility. As I said in the House of Commons on Monday, I mistakenly allowed the distinction between my personal interest and my government activities to become blurred. The consequences of this have become clearer in recent days. I am very sorry for this. I have also repeatedly said that the national interest must always come before personal interest. I now have to hold myself to my own standard. I have therefore decided, with great sadness, to resign from my post as secretary of state for defence — a position which I have been immensely proud and honoured to have held. I am particularly proud to have overseen the long overdue reforms to the Ministry of Defence and to our armed forces, which will shape them to meet the challenges of the future and keep this country safe. I am proud also to have played a part in helping to liberate the people of Libya, and I regret that I will not see through to its conclusion Britain’s role in Afghanistan, where so much progress has been made. Above all, I am honoured and humbled to have worked with the superb men and women in our armed forces. Their bravery, dedication and professionalism are second to none. I appreciate all the support you have given me – and will continue to support the vital work of this government, above all in controlling the enormous budget deficit we inherited, which is a threat not just to this country’s economic prosperity but also to its national security. I look forward to continuing to represent my constituents in North Somerset. Yours ever, Liam 4.19pm: Tory MP Peter Bone says “it’s typical of Liam to put the country first” in resigning. “I think it was largely a media-driven [story]. I didn’t see the hanging offence, I’m afraid,” says Bone. Here is a bit more detail from Fox’s statement: I mistakenly allowed the distinction between my personal interest and my government activities to become blurred. The consequences of this have become clearer in recent days and I’m sorry for this. 4.14pm: This is the second forced resignation since the coalition was formed. The first was the Lib Dem David Laws, who stepped down soon after becoming chief secretary to the Treasury over his expenses. You can see all of the Guardian’s coverage of the Liam Fox story since June here . 4.12pm: The defence secretary, Liam Fox, has resigned after increasing pressure over his links to his unofficial adviser and best man, Adam Werrity. His office has just confirmed the news. In his resignation statement, Fox said he “mistakenly allowed the distinction between my personal interest and my government activities to become blurred”. 4.10pm: The defence secretary, Liam Fox, has resigned. More details soon … How the Guardian broke the story The Guardian’s Rupert Neate broke this story in June and has led the way in uncovering new developments. Here’s how the story unfolded: 27 June 2011 Government weighs into ‘blackmail’ row over 3M and MRSA test 13 July 2011 US firm 3M could summon Liam Fox to give evidence in blackmail case 7 August 2011 Liam Fox forced into U-turn over legal spat with US multinational 3M 18 August 2011 Liam Fox’s friend set up crucial legal meeting 29 August 2011 Liam Fox under fresh pressure over adviser 4 October 2011 Liam Fox faces questions for allowing former flatmate access to MoD 5 October 2011 Charity created by Liam Fox axed after watchdog issues criticism 7 October 2011 Liam Fox was joined by former flatmate on official visit to Sri Lanka Liam Fox had already been warned over Adam Werritty links Liam Fox, his adviser, and an irregular meeting in Dubai ‘Adviser’ Adam Werritty ran charity from Liam Fox’s office 8 October 2011 Businessman met Fox’s friend two months before ‘chance’ Dubai meeting Emails and video footage pile pressure on beleaguered Liam Fox 10 October 2011 Revealed: how lobbyists were paid to facilitate meeting with Liam Fox Werritty remains silent as spotlight falls on his earning and business dealings 11 October 2011 Liam Fox battles to save career as PM gives only conditional support Liam Fox row: Adam Werritty to be quizzed over sources of income 12 October 2011 Liam Fox furious as friends brief against Werritty 13 October 2011 Liam Fox took five MPs to Washington with donor’s money Labour questions £170,000 cost of Liam Fox’s official advisers Liam Fox faces fresh questions on Sri Lanka links Fox and Werritty joined stag party during taxpayer-funded trip to Dubai 14 October 2011 Rightwing Tories rally to Liam Fox’s side Liam Fox and Adam Werritty links Liam Fox Paul Owen guardian.co.uk