Speaking to Fox News, Tommy Robinson, the co-founder of the right-wing anti-immigrant English Defense League (EDL), whose real name is Stephen Christopher Yaxley-Lennon, touched upon "what it was like for him to be behind bars."
Describing the process that convicted him as a "kangaroo court," Robinson claimed that he was put in solitary confinement after moving prisons, where he "spent two months not seeing or speaking to anybody."
He said that during his prison term, he lost "nearly 40lb (about 18 kilograms)" due to a diet of one tin of tuna and a piece of fruit a day.
"I was supposed to be in Her Majesty's Prison Service, not Guantanamo Bay," Robinson noted, in a clear nod to the US military prison in Cuba where some detainees were reportedly tortured.
He bemoaned the fact that he was "drenched everyday" because of "huge heatwaves" in the prison, and that that he had "excrement and spit thrown through the windows."
"In the end I had to block up all of my [prison cell] windows," Robinson said, adding that he still doesn't know "what it is I'm deemed to have done wrong." He claimed that he fell victim to "hatchet jobs" from the "mainstream media."
A Prison Service spokesperson, in turn, rejected Robinson's claims, saying "Mr Yaxley-Lennon was treated with the same fairness we aim to show all prisoners – he had access to visits, television and showers – and it is totally false to say he was held in 'solitary confinement'."
"He was initially placed into the Care & Separation Unit for less than 48 hours while an assessment of the risk to his safety was undertaken by prison staff. He then joined the main prison population," the spokesperson added.
Robinson's interview with Fox News came shortly after he posted a five minute clip on his YouTube channel, in which he pointed the finger at UK authorities over the way they treated him when he was behind bars.
"What they tried to do was to mentally destroy me. That wasn't a prison sentence, that was mental torture. If I was bitter and angry I would accept my own victimhood. I'm not their victim, I'm their target," he underscored in the video.
Earlier, Robinson's supporters set up an online petition for his release, which gathered more than 600,000 signatures, and which specifically claimed that he was put in prison for just "reporting on Muslim grooming gangs."
Robinson was arrested on May 25 and accused of breaching the peace outside Leeds Crown Court, when he streamed an hour-long video inside the courthouse where a trial for a gang rape case was taking place. He was sentenced to 13 behind bars.