The former UK equality watchdog chief, Trevor Phillips, has been suspended from the Labour Party over allegations of Islamophobia.
The Times newspaper reported the anti-racism campaigner is being investigated over past comments dating back years.
Mr Phillips, ex-chairman of the Equality and Human Rights Commission, said Labour was in danger of collapsing into a "brutish, authoritarian cult".
Labour said it takes complaints about Islamophobia "extremely seriously".
A spokeswoman added: "[The complaints] are fully investigated in line with our rules and procedures, and any appropriate disciplinary action is taken."
Mr Phillips was among 24 public figures who wrote to the Guardian last year declaring their refusal to vote for Labour because of its association with anti-Semitism.
He could be expelled from the party for alleged prejudice against Muslims.
Mr Phillips has been suspended pending investigation over remarks, including expressing concerns about Pakistani Muslim men sexually abusing children in northern British towns, according to the Times.
It says the complaint also covers his comments about the failure of some Muslims to wear poppies for Remembrance Sunday and the sympathy shown by some in an opinion poll towards the "motives" of the Charlie Hebdo attackers.
The paper said many of his statements are years-old but that Labour's general secretary Jennie Formby suspended him as a matter of urgency to "protect the party's reputation".
Speaking to BBC Radio 4's Today programme, Mr Phillips stood by his previous assertions that Muslims were "different", adding: "Well, actually, that's true. The point is Muslims are different and in many ways I think that is admirable."
But he criticised the party for taking offence, saying: "I am kind of surprised that what is and always has been an open and democratic party decides that its members cannot have healthy debate about how we address differences of values and outlooks."
Mr Phillips went on to describe the decision by Labour to adopt the definition of Islamophobia agreed by an all-party parliamentary group on British Muslims as "nonsense", as Muslims were "not a race".
He added: "My objection is very simple. That definition said...that Islamophobia is rooted in a kind of racism - expressions of hostility towards Muslimness.
"First of all, Muslims are not a race. My personal hero was Muhammad Ali, before that Malcolm X.
"They became Muslims largely because it is a pan-racial faith. This is not a racial grouping, so describing hostility to them as racial is nonsense."
The Muslim Council of Britain accused Mr Phillips of making "incendiary statements about Muslims that would be unacceptable for any other minority".
A spokesman for the organisation said: "The impact of Mr Phillips' claims from a privileged vantage point is dangerous, providing licence to far-right ideologues such as Tommy Robinson who have seized upon these remarks.
"Mr Phillips would have us believe that he is a martyr for free speech and tolerance. But the fact remains that the deployment of these sweeping generalisations and tropes would not be acceptable for any other community."
Mr Phillips was the founding chair of the EHRC, which is currently investigating anti-Semitism in the Labour Party, when it launched in 2006.
He has previously made documentaries about race and multiculturalism, and now chairs Index on Censorship - a group that campaigns for freedom of expression.
Asked if he would change his language as a result of the suspension, Mr Phillips pointed to this new role, adding: "Frankly, it would be a bit odd if I suddenly decided because I had been kicked out of the club, I couldn't express my beliefs."