If the action of the Burmese junta in refusing to give aid workers visas is unprecedented in modern times, it is the action of a regime like no other in the world.

Nowhere but Burma can one find this combination of brutality, corruption, ineptness, religiosity and xenophobia in a regime which, under one leader and name or another, has hung on to power for 46 years.

It is also periodically racked by power struggles. Where is the junta's 75-year-old strongman, Senior General Than Shwe? Usually Burma's torpid official press is littered with photographs of him and his deputy, Maung Aye, on official inspection visits, but neither has featured in the official media for the past week. Some analysts suspect it could mean a power struggle is under way between those in the hierarchy more open to taking in foreign aid and those, General Shwe probably included, who want to continue to keep the world at arm's length.

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The first soldier to rule Burma was General Ne Win, the army commander-in-chief who seized power in a coup d'etat in 1962. Chief of the army since independence from Britain in 1948, it was his second taste of power, the first time being in 1958 when the civilian prime minister U Nu "invited him to assume the reins of power" temporarily, to help the fledgling democracy out of a mess. For two years Ne Win delivered "the most effective and efficient" government in modern Burmese history, according to the historian Thant Myint-U, then stepped aside.

But the power bug had bitten him and two years later, uninvited, he came back for more. And this time it was for keeps: he was in power for the next 26 years, through his whimsical and destructive "Burmese Socialist Programme Party" imposing what he called "the Burmese Way to Socialism". It meant nationalising everything, closing down all democratic institutions, including the press, eliminating all other political parties, and cutting most of Burma's ties to the outside world, which it hated and feared.

The result was the rapid impoverishment of the country, which at independence had looked to be one of South-east Asia's best bets. Now, with inept and increasingly corrupt generals running everything, the economy began to unravel.

Army rule has been interrupted spasmodically by surges of popular revolt, the most serious in 1988 when mass protests rendered the country ungovernable for months, until a vicious crackdown which left thousands dead. Under great pressure, the regime conceded elections in 1990, which Aung San Suu Kyi's National League for Democracy won by a landslide – but the regime was too scared to recognise the victory. Suu Kyi remained under house arrest, other NLD leaders went to jail or into exile.

The rise of Ne Win's chief of intelligence, General Khin Nyunt, offered a gleam of hope to the regime's opponents. At least he seemed bold enough to open a crack to the outside world, permitting a smidgen of economic liberalisation in the early years of this decade, which saw the arrival of foreign internet and telecom and hotel companies.

In 2002, when Suu Kyi was last released from house arrest, there was the tantalising whiff of a Rangoon spring. But General Nyunt had established his own power structure centred on the National Intelligence Bureau, and Than Shwe, the senior general who had himself grabbed power in 1992, struck against him in October 2004, when General Nyunt was "permitted to retire on health grounds", then immediately consigned to house arrest.

General Shwe abolished his fallen rival's Intelligence Bureau and consolidated his own position, and remains the main power in the land. He was the author of the regime's bizarre shift from Rangoon to Naypyidaw, a new town hundreds of kilometres north, in the middle of the country – supposedly from fear of suffering the same fate as Saddam Hussein.

He is said to have a visceral hatred of Suu Kyi. And he remains rigidly opposed to democratisation: today those parts of Burma not under water will vote in a referendum on a new constitution intended to usher in a sort of democracy – but one constantly loaded in the army's favour, guaranteeing the perpetuation of military rule.

General Nyunt had also demonstrated that he was willing to open the door to at least a handful of foreigners. That is something General Shwe resists at all costs. The regime, known today as the State Peace and Development Council, cannot forget that 82 per cent of Burmese voted against them in the 1990 election: they know that the vast majority of their countrymen are deeply estranged from them.

The huge demonstrations by monks last year showed that, however cowed and bullied, ordinary Burmese are angry enough to rebel. The generals fear the ordinary people could rise up again at any time – and that a flood of foreign aid workers could be the spark to ignite the next revolt.