With the rise of Donald Trump and the alt right in the US, TV star Louis Theroux does not think he could have made his controversial documentary on American neo-Nazis now.

The broadcaster said he would have to think very carefully about making it today because he would not want to be seen as “popularising hate”.

He made his Louis And The Nazis documentary in 2003, interviewing several white supremacists and attending skinhead rallies, and when it was broadcast it was described by critics as “sinister and unsettling”.

Theroux said that now, with the rise of the alt right and extreme views becoming more mainstream, he would have to consider carefully whether he was giving these people a platform.

“I’m on board with the whole idea that platforming is something that should be thought through carefully,” he said.

“The world has changed a lot since I started making my programmes and a lot of thought went into how we made them.

“Back in the days of when I made Louis And Rhe Nazis, which is as far down the road I have gone with that, I spent days, if not a couple of weeks, with basically card-carrying national socialists – people who had the most extreme version of Nazism as you can imagine.

“I think the reason I felt it was OK was that it was so far outside the window of acceptable discourse that it was verging on pathology.

“When you get that extreme it almost provides a certain safety – there is almost no danger of anyone seeing it and thinking that looks sensible.

“If they had been closer to the mainstream you might have imagined we are giving them some sort of currency. It was so palpably outlandish, it felt there was a reason to do it.

“In this day and age, when you have members of the alt right who, in some cases, have crypto-fascist views or coded racist views and some not-so-coded racist views, and there is a trickle up or trickle down to the White House, suddenly you are in a different space.

“You are in danger of lending credence to or popularising hate and, as a result, I have been very wary of doing that.”

Theroux, who was speaking at the Cheltenham Literature Festival, was asked whether he could have made Louis And The Nazis today.

“I think you’d have to think it through, I think it really depends,” he said.

“I tend to think it also depends on the balance of the programmes I am making.

“I make three or four in a given year and I think it would need to be off-set and we’d have to think why we are making it. Is there a compelling reason?”

The 49-year-old has recently published his autobiography titled Gotta Get Theroux This, of which six chapters are focused on his relationship with Jimmy Savile, who had featured in one of his films.

“For a while I thought I’d write a book about Jimmy Savile,” Theroux said.

Savile sex abuse investigation
Six chapters of Louis Theroux’s autobiography focus on his relationship with Jimmy Savile (PA)

“In the end it was an extraordinary thing to live through. It was very stressful, and I felt it was a weird education in human nature, in both my successes and failures.

“I grew to slightly like him, I quite liked him and spent time with him and regarded him in a friendly way.

“I knew there was a dimension to his life that I didn’t fully understand, I genuinely didn’t think that was likely to be what it turned out to be, which was that he was prolific serial paedophile and sex offender.

“There was guilt because, when he was unmasked, a part of me to begin with thought ‘I’m not sure that all could be true’. In other words, it took a while to wrap my arms around the scale of how much he had done and then I had to adapt myself to that.

“Then there was a part of the process of a weird feeling of almost feeling a guilt I didn’t need to feel.”