Overcrowded, infested, and brutal, this sprawling collection of brick and concrete buildings houses prisoners from across Burma in small dirty cells. Most are political prisoners, the overwhelming majority Burmese nationals, serving up to 25 years for "subversive acts" such as speaking to United Nations researchers.
But in one of the cells set aside for prisoners in solitary confinement an Englishmen has sat for the past three months, crushing cockroaches and reading a hard-back copy of the New English Bible.
His favourite passage has been John viii, 32: "You will know the truth and the truth will set you free."
James Mawdsley, 25, was arrested three months ago and sentenced to five years in Insein for illegal entry to the country.
Yesterday, in a surprise move, the Burmese regime - one of the most brutal in the world - released Mr Mawdsley and ordered him to be deported back to Britain.
He is lucky. This is the second time he has been deported from Burma in the past 12 months.
Last year he was held for 29 hours after being arrested when he had chained himself to railings outside a school in Rangoon, having scrawled pro-democracy slogans on a wall. When he was arrested last April he was said to be distributing pro-democracy leaflets.
Tomorrow marks the 10th anniversary of the crushing of the pro-democracy movement in Burma by the military regime - the State Law and Order Council (Slorc) now renamed the State Peace and Development Council. About 10,000 citizens were killed by the regime as it sought to restore its iron control. International observers believe that since then thousands more have been raped, tortured, imprisoned and murdered.
In addition to summary beatings, torture, slave labour and murder, the military have started to use rape as a means of repression.
The Bangkok-based Sunday Nation reported earlier this year that soldiers were being told they should routinely use sex against tribal women as a means of dominating them. The United Nations Special Rapporteur has described "an atmosphere of pervasive fear in Burma."
The human-rights group Amnesty International said: "Tomorrow's anniversary marks not just 10 years of suffering for Burma's people, it marks a decade of struggle against the odds for basic human rights and fundamental freedoms.
"It is also time for the international community to re-commit itself to supporting the Burmese people in their cause.
"For all the statements, for all the sanctions, for all the promises of engagement producing results, things in Burma have only got worse."
Different countries engage with Burma to different degrees. At one extreme, China is a supporter, financially and militarily of the regime, while in the United States many states and cities have laws prohibiting businesses dealing with the regime. Britain's position is perhaps somewhere in between.
When it came to power, the Labour government stopped trade missions, banned arms sales and imposed visa restrictions. It says it also officially discourages companies from doing business in Burma.
Yet the Government will not impose full sanctions, claiming it is not allowed to by European Union regulations.
That may change. The Foreign Office minister Derek Fatchett told The Independent he was working on a series of proposals that would toughen Europe's stance on Burma.
If taken up, they would in effect be virtual sanctions.
"We are working on a series of proposals to strengthen the position," he said, explaining that these would "bring Europe's position more into line with Britain's.
"Sadly, how quickly we move will depend on how the situation develops in Burma. There is a very good reason to expect there will be a worsening of the situation."
These proposals will receive the input of Aung San Suu Kyi, leader of the banned National League for Democracy, who is under house arrest in Rangoon.
Last week she was prevented from leaving the capital to meet supporters of her party, which at elections in 1990 won 82 per cent of the vote but was prevented from taking power.
Her view on sanctions is clear. "I call on governments to enact sanctions against the oppressors of my people in the name of democracy and decency," she has said.
One British company that has ignored her demand is Premier Oil.
The company's interests in the Yetagun oilfields are worth an estimated pounds 160m.
"Premier Oil has never used and would never use anything made by slave labour," said a spokesman. The company's "global responsibilities" brochure adds: "Premier does not get involved in politics."
The timing of Mr Mawdsley's release is no coincidence. The Burmese regime is desperate to improve its image and attract overseas investors to save an economy where inflation is 40 per cent and there is an estimated $200m (pounds 125m) left in foreign-currency reserves.