I HAVE to say that Louis Theroux used to annoy me.

When he did his ‘celebrity’ interviews I always felt he played the role of naive interrogator a little too much.

It’s only when he has concentrated on more serious topics that he’s started to win me over.

On Sunday his documentary Miami Mega-Jail was compelling and disturbing viewing.

Theroux was somehow given access to the prisoners on remand in one of the most violent maximum security jails in America.

It was truly shocking. Prisoners were in effect allowed to run their own cells as they liked.

Often more than 20 inmates were kept behind bars with the laws of the jungle appearing to rule.

Newcomers were challenged to prove themselves by fighting for the right to a bunk.

Beatings were commonplace, sex assaults not unknown and the guards appeared either powerless or unwlling to get involved.

That didn’t stop Louis from going into cells to talk to some of the most violent offenders.

You could tell the guards weren’t happy with the idea but in he stepped.

The prisoners eyed him up like a pride of lions who had spotted a lonely antelope.

One offered to fight him for his shoes. Louis wisely declined.

It was gruesomely fascinating viewing — and every credit to Theroux for having the courage to introduce us to it.