LIMA, Peru - Peru's best-known prison inmate is eccentric, irreverent and narcissistic and almost offhandedly takes credit for his older brother's ascension to the South American nation's highest office.

President Ollanta Humala insists he's estranged from his brother Antauro, whose antics have increasingly made news in Peru, climaxing with a string of revelations this week.

But Peru's chief executive seems unable or unwilling to rein in his brother, and his popularity has apparently suffered as a result.

"For me, having made my brother president is a cross I must bear," Antauro Humala, 47, said this week during a court hearing on whether he bribed prison staff to allow a lover entry to his cell outside visiting hours.

He was soon back in the spotlight: A TV channel broadcast video of him smoking marijuana in prison.

"I was offered it," Antauro Humala later said in a newspaper interview. "It's not a crime to consume cannabis."

Peruvian law permits citizens -- though not prison inmates -- to possess small amounts of marijuana. Antauro Humala did not address the question of how it was smuggled into prison.

Brothers in arms as they rose through the army's ranks, Ollanta and Antauro shared nationalistic ideals before staking out separate paths. The older brother forged a career in politics and was elected last June.

The younger brother, who retired with the rank of army major, opted for a more violent path.

On Jan. 1, 2005, he led an assault on a police station in the highland city of Andahuaylas, seeking to trigger a revolt that would force democratically elected President Alejandro Toledo to step down. The insurrection failed. Four police officers were killed along with two followers of Humala.

The day before the revolt, Lt. Col. Ollanta Humala was removed as Peru's military attache in South Korea, cashiered for disloyalty to Toledo.

Antauro Humala was later sentenced to 19 years prison for manslaughter, rebellion and kidnapping.

The two brothers had first gained fame in 2000, when they staged a bloodless, somewhat quixotic military revolt against then-President Alberto Fujimori, who shortly thereafter fled into exile.

During the next four years, Antauro crisscrossed Peru with former army reservists, propagating the "ethnocacerist" doctrine that his father Isaac taught his children. Expounded in pamphlets entitled "Ollanta," the doctrine argues that Peru's natives are ethnically superior to the white Europeans who have dominated politics and the economy since colonial times. Antauro Humala says that crusade helped his brother win the presidency.

The president disavows both the philosophy and his brother.

"I'm directly against everything he says," President Humala said Sunday in an TV interview broadcast a few hours before the pot-smoking video aired. "I don't share anything with him, not in what he does or what he says or what he thinks. And that's nothing new."

The president, who is 49, also said he never approved any benefits for his imprisoned brother.

"I have not and will never give an order to favour anyone. I have 30 million brothers," President Humala said, a reference to Peru's population.

He was responding to allegations of first-family favouritism over brother Antauro's March 3 transfer from the high-security Piedras Gordas prison to a cell nestled in a military barracks.

Previously, two directors at Piedras Gordas had lost their jobs over favoured treatment of the first-family prisoner: TV interviews with him had been recorded inside the prison and he was using a cellphone.

After the marijuana-smoking video went viral on the internet, the National Penitentiary Institute, or INPE, replaced the directors of all 18 of its Lima prisons. Its director, Jose Luis Perez, said in a radio interview that the shake-up was unrelated and had been weeks in the works. But he said Antauro Humala was his No. 2 headache after corruption.

Prison officials had already been embarassed when newspapers published a photo this month that Antauro Humala took with a cellphone showing him hugging a woman in what appeared to be his cell.

After the pot-smoking video emerged, a flood of media reports put Antauro Humala's prison life at the centre of national attention.

Not only did he allegedly have a TV, iPhone and other amenities in prison against regulations, he was also exchanging emails with people who were seeking jobs in his brother's administration as well as recommendations, reported Cuarto Poder, a news show on America TV. There is no evidence he ever forwarded any of those appeals.

Peruvian media also published emails that Antauro sent to lovers, one of whom had had appeared earlier in a widely published photo showing her wielding a pistol in a provocative pose.

Some of the emails were signed "Copper Adonis," others with the equivalent of "Your Incan Prince Charming."

It's no secret that well-heeled inmates in Peru's prisons often purchase privilege from poorly paid penal officials. That's common in developing-world lockups.

The bigger scandal has been Ollanta Humala's near silence until this week on his notorious first brother.

A March 18 Ipsos Apoyo opinion poll showed the president's approval rating dropped six points to 53 per cent in the month after Antauro Humala's transfer from Piedras Gordas to prison inside the military barracks.

On Sunday, the president insisted he would continue his policy of non-intervention.

"The issue of Antauro is relegated to the judiciary and INPE and that is where it's going to stay," the president added.