text: The activist, who says he was himself a victim of bullying, told BBC Newsnight that the dossier was given by Ben Howlett, now an MP, to Lord Feldman.
  Lord Feldman insists he was not aware of any complaints before August 2015.
  Two activists involved in producing the document say it named Mark Clarke.
  Mr Clarke is the volunteer organiser at the heart of the bullying scandal which has bedevilled the party since September.
  He has been accused of bullying, sexually harassing and planning to blackmail other activists - allegations he has robustly denied.
  Patrick Sullivan, who runs a Conservative think tank, said hard copies of the 2010 dossier were handed to Lord Feldman and Tory co-chair Baroness Sayeeda Warsi.
  His testimony appears to contradict the account of Lord Feldman, a close friend and political ally of the prime minister.
  The Tory chairman has maintained consistently that he was "wholly unaware" of the allegations against Mr Clarke until August 2015.
  Mr Sullivan told Newsnight that Mr Howlett, MP for Bath, had decided to tackle widespread bullying within the party's young activists after being elected to a second term as chair of Conservative Future, the party's youth wing, in 2010.
  Mr Sullivan said: "He had a strong anti-bullying stance in the campaign because there had been a culture of bullying. As soon as he was elected Ben [Howlett] and myself helped compile a dossier and that dossier was given by Ben to Lord Feldman and Sayeeda Warsi."
  He said that complaints had been made to the party about Mr Clarke's behaviour even before 2010 when Mr Clarke was removed from the party's list of approved candidates.
  "The dossier is not the only thing," Mr Sullivan said. "There were complaints about Mark Clarke in 2008. So complaints about Mark Clarke had been something that Conservative Central Office have known about for a very long time."
  Mr Sullivan said his own bullying at the hand of Mr Clarke seriously damaged his health: "I got depressed. I felt I couldn't leave my home. I felt isolated." He said Mr Howlett had also been a victim of Mr Clarke's bullying.
  They assembled the dossier over the course of a week along with a third activist. It contained first person accounts from activists who had been bullied, alongside newspaper reports of bullying incidents which were already in the public domain.
  Mr Sullivan says he first challenged the culture of bullying in the party in 2008 after an 18 year-old woman was "spectacularly" bullied in the run up to a Conservative Future election.
  He said: "Mark Clarke had a preferred candidate and as a result he started bullying and intimidating people who were opposing that candidate. That was when I first realised how bad he was."
  Mr Sullivan said he made a speech inside CCHQ attacking the bullying culture in front of Mr Clarke and others. "As a punishment for making that speech I was isolated like a pariah," he said.
  More on this story:
  Memo warned Tory bully 'dangerous'
  Ministers pull out of conference amid bullying scandal
  Grant Shapps quits amid Tory bullying claims
  Lord Feldman: The key questions
  Listen: Mark Clarke profile for Radio 4
  Tory 'bully' was backed by party bosses
  Tories 'failed to act' on 'institutionalised bullying'
  Watch: Newsnight investigation into Tory bullying allegations
  Mr Howlett had previously told Newsnight that "Feldman has known about Clarke for a long time" but declined to discuss the contents of the dossier.
  Two of the document's authors said it named Mr Clarke among a number of alleged bullies involved with the party's youth wing.
  Mr Sullivan said Baroness Warsi had been "very vigilant in regard to bullying" but that tolerance of bullying had increased after she left Conservative Campaign Headquarters (CCHQ) in 2012.
  The bullying scandal has gathered pace since a young activist, Elliott Johnson, took his own life in September. Elliott Johnson had previously complained to CCHQ that he had been bullied by Mr Clarke, and named Mr Clarke in a letter left to his parents.
  Mr Clarke has denied all allegations of inappropriate behaviour. He has told Newsnight he was not aware of any "dossier" mentioning him in 2010.
  On Tuesday night Elliott's father Ray told Newsnight: "If Lord Feldman and CCHQ were fully aware of allegations of bullying being made as long ago as five years and they didn't act upon it, then it just confirms my view that they really should have taken action against bullies in the first place and failed to do so."
  "They failed to protect my son and they failed to protect many other young activists and they should stand up and take responsibility for it."
  Former co-chairman Grant Shapps resigned last month as a development minister after it emerged that he had given Mr Clarke a formal role in CCHQ despite previous concerns about his behaviour.
  However both Number 10 and the party have been determined to protect Lord Feldman who has been a member of the prime minister's inner circle since they met at Oxford.
  Increasingly, however, Lord Feldman has come under pressure, both over his account of when he first became aware of allegations of bullying, and over whether he reacted appropriately to a slew of complaints received in August of this year.
  Last week Newsnight revealed a former CCHQ worker submitted a memo to a senior party official in August claiming that Mr Clarke was "sociopathic" and "dangerous" and warning that there could be "devastating" consequences if he was not kept away from the party's youth wing.
  Asked whether he believed Lord Feldman should have done more in response to the memo, Mr Sullivan said: "Yes I do, I think it was quite shocking that Mark Clarke was able to continue with his RoadTrip 2020 whilst this investigation was process."
  Lord Feldman said on Tuesday night: "I was wholly unaware of allegations of bullying and inappropriate sexual conduct by Mr Clarke prior to August 2015. Such behaviour is abhorrent to me and had this been brought to my attention I would have taken immediate action to investigate, as I have done since I received the complaint in August 2015."
  More on this story on BBC Newsnight at 22:30 GMT on Tuesday 8 December on BBC Two. You can catch up afterwards on iPlayer and follow Newsnight on Twitter, Facebook and YouTube
target: A 20-page dossier detailing a culture of bullying within the Conservative Party's youth wing was handed to party chairman Lord Feldman in 2010, according to a former activist.