International aid agencies were struggling last night to digest the announcement by Ban Ki Moon, the UN Secretary-General, that foreign aid workers will be allowed to enter Burma freely and visit the areas devastated by Cyclone Nargis.

The unexpected agreement came during a two-hour meeting with the country’s supreme leader, Than Shwe, in the capital, Naypyidaw. If the promises conveyed by Mr Ban are fully implemented, it will represent a life-saving breakthrough for the stricken areas of the Irrawaddy delta, and personal triumph for Mr Ban.

Aid organisations and human rights groups were puzzled last night over whether General Than Shwe has genuinely changed his mind, or if this is just a ploy to divert the intense international pressure on his regime with the appearance of a breakthrough.

Since the cyclone struck on May 2, the Burmese junta has refused most visas to foreign aid workers and banned all of them from the disaster zone itself. The aid operation has consisted of patchy relief organised by the Government and strenuous, but inadequate, efforts by Burmese staff of local and international NGOs.

In the past few days foreign governments have floated the idea of a relief operation headed by South East Asian, Indian and Chinese officials, who arouse less suspicion in the xenophobic junta. According to Mr Ban, this compromise will not be necessary.

“I had a very good meeting with General Than Shwe and particularly on the aid workers,” Mr Ban said after the meeting yesterday. “He has agreed to allow all the aid workers, regardless of nationality. I urged him that it would be crucially important for him to allow aid workers as swiftly as possible and all these aid relief items also be delivered to the needy people as soon as possible.”

A UN official told foreign reporters accompanying Mr Ban that General Than Shwe had said that he “saw no reason” why genuine humanitarian workers should not travel to the Irrawaddy delta, where between 78,000 and 200,000 people died and 2.4 million others lost their homes or livelihoods.

Many aid workers in the former capital, Rangoon, had low expectations of Mr Ban’s visit, after General Than Shwe declined repeatedly to take his phone calls or answer letters. On Thursday Mr Ban was taken on a carefully organised tour of government-run refugee camps.

“I saw the saddest of things, so many lives lost,” he said. “We work hard in our lives for ourselves and our families and then in a moment, it is gone. I’m humbled, humbled by the scale of this natural disaster, the worst your country has ever experienced, and humbled by the courage and resilience of the Myanmar people.”

There was no official word from the Burmese Government on the content of the meeting, but it is clear that the test of any agreement will be measured in improvements on the ground. “The world is watching,” Mr Ban said. “Implementation will be the key.”

NGOs sounded a note of scepticism. “We’ll believe it when we see the aid workers on the ground in the delta,” Zoya Phan, of the Burma Campaign UK, said. “The generals have a long track record of lying to the UN. If the regime is genuine, then we’ll know within 24 hours, as they’ll take down the army checkpoints which are stopping Burmese and international aid workers getting into the delta.”

According to UN officials, the Government indicated that civilian boats and ships would be permitted to deliver aid – making it all the more unlikely that British, French and American warships off the Burmese coast would be allowed to play any part in the relief operation. President Sarkozy of France said yesterday that the 1,500 tonnes of aid on the amphibious assault ship Le Mistral might have to be delivered by ferry after being off-loaded in neighbouring Thailand.

Mr Ban left for Bangkok last night, but will return tomorrow for a “pledging conference” at which donor countries will set out their contributions to the relief effort.

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