He will take with him, according to an unofficial spokesman, a 'handful of Iranian dust' just as his father, Reza Shah, did when he was exiled in 1941. The Shah must know that, like his father, he may never return. But he may also have hopes that the situation in his country will eventually permit him to return as a constitutional monarch, or at least let his son assume the throne.

The Shah, it is believed, will leave with only a small entourage. Besides his wife and three children, there will be only a few guards and one senior protocol official. The Shah will meet President Anwar Sadat before making a pilgrimage to Herbola, the great Shi'ite shrine in Iraq, and to Mecca, palace sources said. His final destination will probably be America, although the Shah is not sure that he wants to stay there, one source said.

Meanwhile, other evidence - including statements by a mysterious young man claiming to be an unofficial spokesman of the Shah - suggests that there may be a Royal strategy to preserve the Bakhtiar Government, the form of the monarchy, and at least a faint chance for the Shah or his son to return.

The idea appears to be to confront Ayatollah Khomeini with a choice between dealing with the moderates or facing military intervention and massive repression. The situation itself suggests that such a coup might be attempted if the Ayatollah goes for a takeover.

The 'Imperial emissary', a young man named Hossein Amersadighi, who has no official position at the court, is clearly given to fantasy and inflating his own role, but some of what he said in a lengthy briefing to the foreign press yesterday is probably true.

His general message was a warning to Ayatollah Khomeini that, unless he compromised with the Bakhtiar Government, there would be a coup and 'initially the army would have to kill two or three million people. There would be mass murder'. The Shah had made a great sacrifice, now it was up to Ayatollah Khomeini to do the same.

If Hossein's claim to intimacy with the family is true, he gave a fascinating glimpse into the mind of the departing monarch. The Shah had reached the point, he said, where he, 'no longer gives a damn', and he was 'bitter about the people of Iran'.

With the Shah's departure imminent, the Bakhtiar Government is hoping against hope that it can prevent, in the words of one Minister, 'the exchange of one despotism for another'. Every speculation now hinges on the actions of Ayatollah Khomeini and on the question of whether he will deal with the Bakhtiar Government and other moderates, or go ahead with his plans for total revolutionary change.

The Prime Minister, Dr Shapur Bakhtiar, told the Senate yesterday: 'Khomeini has absolutely nothing against me, and I am in touch with him and with other religious leaders'. The Senate gave Dr Bakhtiar a vote of confidence. That of the Lower House is expected today. Privately, Ministers are grasping at every bit of evidence that Aytollah Khomeini's real position is more flexible than his statements would suggest.

'I think he will make the right decision' a source very close to the Government said. Supporters of the Government hope that its confidence about Ayatollah Khomeini's 'realism' is not just wishful thinking. One, asked what he thought were the chances of Dr Bakhtiar's standing against the ayatollah, pointed wordlessly out of his office window.