The Prime Minister, who was consulted before the Queen intervened, has been acting behind the scenes in discussions over the princess's future.
It is widely believed that the kind of "ambassadorial" role she is seeking would have to be preceded by her agreement to a divorce, although the Prime Minister kept firmly to the politician's convention of neutrality yesterday, saying he had nothing to add to Wednesday night's statement by the Palace.
"It's a matter that's being dealt with. I've nothing further to add on that," Mr Major said during yesterday's visit to Northern Ireland. But Michael Heseltine, the Deputy Prime Minister, told ITN: "Obviously it's a very sad announcement but I think it had become inevitable in the circumstances and the Prime Minister told the Queen that he agreed with her judgement."
Tony Blair, the Labour leader, while avoiding advocating a divorce as such, firmly backed the idea of the princess being given a distinctive role in public life in the event of one.
"It is very sad for them personally and my sympathy is with them," Mr Blair said in a BBC radio 4 World at One interview.
"It's also the case that it's immensely difficult for them to work out their future path now.
"There are no immediate constitutional implications, that is true. But I think that most people, myself included, would like to see, should a divorce take place, some role for Princess Diana and some chance for her to use the ambassadorial abilities that she has in the interests of the country."
Sir David Steel, the Liberal Democrat elder statesman, said most people wanted the couple to get on with an amicable divorce and the Prince to end up as King and Diana to get a proper role in public life.
Mr Blair added: "These things are always difficult to work out but I'm sure that there will be a proper opportunity to discuss the kind of role she might have. I think that most people, myself included, would like to see such a role. She's an immensely popular figure. She's held in great esteem and it will be good to see her being able to perform some useful role for the country. I think there can be discussions about the nature of that role.
"It's not a matter of party politics at all, it's a matter of trying to come to terms with what is a very sad and difficult situation for the Prince of Wales and Princess Diana and seeing how the best can be achieved for them, their family and obviously for the country as well."
James Hill, the MP for Southampton Test and chairman of the Conservative backbench constitutional affairs commitee, said: "There is nothing in the constitution that says that the heir to the throne cannot have a mistress, and since the Prince has said he is not going to marry I believe this has clarified that aspect.
"The Princess might have been inclined to dig her heels in had she thought that as soon as he had got his freedom he was going to marry the 'other woman'. So we are making progress.
"We have got to get her a responsible role in international affairs. There remains the question of a financial settlement, her ability to see her sons at any time, and a grace and favour residence, at which point we will be heading towards calmer waters.
"I think the Queen was very wise to intervene at this stage, otherwise there would have been another two or three years of backbiting. We could not have had a situation where the two households were conflicting forces."
Paddy Ashdown, the Liberal Democrat leader, urged a speedy divorce, saying: "The end of a marriage is a very sad event. But it is now plain to all that, sadly, this marriage has ended. There is no point in prolonging the pretence.
"It is in the interests of both parties, their children and the public duties that they must perform that the situation is clarified by formalising the separation with a divorce as soon as this can practically be arranged."Reuse content