Suu Kyi's release is a tribute to her courage and the value of sanctions

Her re-release is a direct result of international sanctions. The regime only moved because it faced economic meltdown

I listened to it all from afar, wishing I was there. I could picture the scene: the metal barricades, the secret policemen scuttling around, the reporters and the supporters counting down the hours. And beyond the barricades, University Avenue, the long, broad boulevard in the heart of Rangoon down which I'd walked seven years ago when the Burmese junta first freed Aung San Suu Kyi from house arrest. That was in the days when I could still get into the country. These days my presence is regarded as undesirable, though if the Burmese ambassador here in London wishes to issue me a visa I will be on the next plane.

The release of Aung San Suu Kyi is a victory for her own steely courage, and for the principle of carefully and intelligently applied international pressure. I will come back to intelligent sanctions later, for they have a much wider relevance in a world where we are confronted with brutish regimes that seem impervious to the claims of civilised behaviour. But first Burma, and what may or may not be the beginning of a democratic transition in one of the most repressive societies on earth.

History teaches us to be cautious when it comes to the Generals in Rangoon. On that sweltering morning back in 1995 when I walked into Aung San Suu Kyi's compound there was a genuine sense that Burma was edging towards liberty. To be fair, she herself was circumspect, reminding the press and her own supporters that her physical freedom didn't amount to much while the Generals continued to hold all political power.

But this was still a time when the world believed that peaceful revolutions could shift tyrannical regimes. We thought the release of Suu Kyi might herald peaceful demonstrations; these could build into a mass movement and edge the junta from power. It was just a year after the South African elections and many saw in Suu Kyi a new Mandela who would combine peaceful mass action with political negotiation.

I watched Mandela closely in South Africa and have been lucky enough to get to know Aung San Suu Kyi reasonably well. Both have a stoic capacity to endure, both are believers in negotiation and both consistently refused to draw any distinction between their own liberty and that of their people. As Mandela once wrote from his prison: "My freedom and yours are inseparable." But the most important similarity can only be described in blunt terms: they are both as tough as nails. So when the Burmese regime prevented Suu Kyi from campaigning and locked her up again, she didn't simper and try to make a backdoor deal.

Just as Mandela could have done a deal which would have seen him go free years earlier (but at the expense of broader change), Aung San Suu Kyi will not be tempted by any deal which makes her a pliant partner of the junta. She was profoundly influenced by the South African example. When I met her she described how she had listened intently to the BBC radio reports of the transition and she bombarded me with questions about how Mandela and his comrades had persuaded De Klerk to hold multiracial elections.

She was particularly keen to learn about sanctions and one of her first acts after being freed was to call for an international tourism boycott of Burma. Her re-release this week is a direct result of international sanctions. The regime only moved because it was facing economic meltdown; it desperately needs foreign investment and tourists' hard currency.

The price of rice – the local staple – is out of control while wages remain static. It took 40 years of military misrule to create this situation; 40 years of official corruption on a blinding scale. Yet the Generals have proved to be susceptible to pressure. They may be greedy and brutal but they are not stupid. The ruling clique has taken a long look down the road and seen the choice: make a deal with a democratic leader such as Aung San Suu Kyi or face the ultimate possibility of violent overthrow. I think it will take time and I'm sure the junta will still try to undermine Suu Kyi. But by acknowledging their critical susceptibility to international pressure the junta has conceded vulnerability.

So does this mean that sanctions are a weapon to guarantee change? Look around at some other countries and the answer is, self-evidently, no. Why did they work in South Africa and Burma but not against Saddam or – so far at least – Robert Mugabe? Sanctions are often described as a blunt weapon but they needn't be. Just as the political dynamics of each international crisis are different, so too must be any attempt to impose punitive measures on tyrannical regimes.

It may seem curious to give the Burmese junta credit but they proved themselves to be pragmatists. And sanctions only work when those targeted believe there is some benefit to be gained from conceding to the pressure. In South Africa the apartheid state recognised that sanctions were the first step in an international campaign that could have fatally undermined white rule. The outflow of capital and dearth of investment that accompanied the township rebellion of the mid-1980s created conditions where an autocrat such as P W Botha could be replaced by a pragmatist such as F W De Klerk.

When you are dealing with Robert Mugabe the calculation is rather different. In the Zimbabwean context sanctions will not persuade Mugabe to step down but they could foster conditions that accelerate his demise. The specific circumstances of Zimbabwe – an economy in free fall, a looming famine due to drought and mismanagement – mean that sanctions will increase public anger with the regime: the people of Zimbabwe have had access to free information and, albeit limited, democratic expression. They cannot be fooled into believing that sanctions are the weapon of imperialist aggressors.

In Iraq, where there is no free media and where Saddam's reign of fear ensures no democratic expression, the regime successfully absolves itself of any responsibility for the sanctions. Thus sanctions impose no pressure on the regime while punishing Saddam's most conspicuous victims: the Iraqi people. Saddam has made clever propaganda use of the effects of sanctions. They don't work and should be dropped.

As for Burma, it was interesting to hear the Foreign Office minister, Ben Bradshaw, refusing to encourage people to visit the country. The international community will wait and see. If Aung San Suu Kyi is allowed to organise and campaign, and if there is a commitment to democratic elections, then sanctions will go.

Again, the South African example is hugely instructive. In tandem with every significant move made by the De Klerk government the sanctions were relaxed or dropped altogether. Who knows but soon enough we may be talking of President Suu Kyi. And those nice men at the Burmese embassy in London might relent and give me a visa to watch it all.

The writer is a BBC Special Correspondent