The revelations have already prompted a former lover, Nigel Hart, to kiss and tell - disclosing how he once discussed with Mr Portillo whether a gay lifestyle could harm a politician's chances. Mr Portillo allegedly replied that the time could come "when no one will care". The question now is whether that time has arrived in Kensington and Chelsea.
When Mr Portillo was confronted with Mr Hart's tabloid revelations I knew exactly what he was going through. As he hid from the media circus I remember my own "outing" by a tabloid newspaper five years earlier. I did everything I could to run away from the rat-pack banging on the gate of my home. The feeling that one's life is being stripped bare for everyone else to mock, gossip, to laugh at and to ridicule is virtually impossible to put into words. There is only one response: to escape.
Mr Portillo's reaction seems to have been the same as mine and for several weeks he has been abroad. He probably dreads the telephone ringing in case there is more bad news. As a relatively minor MP, the press lost interest in me but there were still major aftershocks, not least the recognition that there would be further questions to answer.
Mr Portillo is about to face this aftershock and from tomorrow morning, if he is selected, he will no longer be able to slink in and out of side entrances, for fear of demonstrations or awkward queries from the press.
Until his election defeat Mr Portillo had showed an enviable ability only to address issues he wished to discuss and he progressed - like a hovercraft skimming the political waves - with only the occasional bump. From grammar school, to Peterhouse, Cambridge; from Conservative research department to special adviser; from MP to cabinet minister, his progress was effortless.
Now it is all so different as he seeks to resurrect his political career. An embattled Tory party needs Mr Portillo's skills more than ever and even William Hague, who might have reason to fear Mr Portillo's return, is supposed to have said "we need him back".
But just as the sun begins
to rise on Mr Portillo's return, along comes a former gay lover, a hundred prying newspaper journalists and television cameramen and, now, Peter Tatchell and his supporters from the gay pressure group OutRage! .
Can Mr Portillo turn it round? More importantly, can the Conservative Party handle it? The next three weeks will give the answers. Mr Portillo will go to this evening's final round for the constituency party nomination with a mixture of dread, anxiety and quiet confidence.
Outside the hall, gay rights protesters will argue that he cannot run away from his past. Inside, however, Mr Portillo will relish giving the speech of his life in the hope of bringing to an end his 30-month stint in the political wilderness.
If he is selected it will show that the Conservative Party is prepared to "forgive" a candidate the early dalliances of his student days. Rejection would send out a message that the party cannot even cope with former gay candidates, never mind openly gay MPs.
The dilemma for local Tories is that if they select Mr Portillo, Mr Tatchell could stand against him. Far better, some say, to play safe with Derek Conway, the former government whip.
There is a great opportunity for Mr Portillo to do himself, his party and even gay rights a favour. But it will require a degree of courage forcing him to answer questions which hitherto he has avoided.
These include "How did you stop being a homosexual?" "Were you and do you remain bisexual?" "Do you intend to stick to your past voting record on gay rights?"
No evasion by refusing to debate on public platforms or refusal to hold press conferences will make Mr Tatchell or the press go away. I believe Mr Portillo should take a risk and volunteer the answers immediately after tonight's meeting.
He made an excellent speech during the party conference in 1997 - where he hinted at greater tolerance - on which he can build reasons for changing his mind on his past anti-gay voting record. At a stroke he can drag the Conservative Party into the 21st century, distance himself from the charge of hypocrisy and relieve us of a distracting OutRage! campaign.
Failure to be bold may leave either Mr Conway the winner, or provide three weeks of hell for Mr Portillo, who would be constantly on the lookout, yet again, for escape routes from tricky questions.