The Home Secretary, his ex-lover and an increasingly bitter war of words

New allegations about David Blunkett and relationship with 'Spectator' publisher Kimberly Quinn hit Westminster

The simmering war of words between the Home Secretary David Blunkett and his former lover Kimberly Quinn became a public and intensified argument last night. Heaven knows where it will take the protagonists and, with them, the Government.

The simmering war of words between the Home Secretary David Blunkett and his former lover Kimberly Quinn became a public and intensified argument last night. Heaven knows where it will take the protagonists and, with them, the Government.

Westminster works to its own rules, different from those on which moralists or the world at large base their judgement. One informal rule says that ministers do not have to answer for what they do in their private lives, provided that it does not impinge on their work.

That is why at least partof the latest allegation about Mr Blunkett, however trivial it may seem, has to be taken seriously. It has been suggested that he helped to speed up an application for a visa from Leoncia Casalme, a Filipina nanny working for the woman then known as Kimberly Fortier, the publisher of The Spectator magazine.

It was serious enough to produce the first public comment from the Home Secretary on a story which has bubbled in the press for weeks, accompanied by a long statement that was due from his political office. Up until now, Mr Blunkett has said nothing, and has instructed his staff and pleaded with friends to do the same.

Readers of newspapers that are more robust in treating private lives than this one have been treated to vast amounts of information about the Home Secretary's affair with Kimberly Quinn, as she is now known. It has all come from people who know one or both of the estranged former lovers, usually speaking without their authority.

The two parties have taken up such irreconcilable positions that it seems the dispute over who is the father of Mrs Quinn's two children, one of whom is not yet born, is on the way to becoming a sensational court case.

Almost anybody in the outside would say that the most important aspect of the whole sorry affair is the welfare of the two children. What comes next, they might say that the health of the mother, who is off work until May with a stress-related disorder. There is also the personal hurt being endured both by Mr Blunkett, and by Stephen Quinn, Mrs Quinn's remarkably forgiving husband.

No one outside Westminster would think it really mattered if Mr Blunkett gave his lover's nanny a bit of help filling in a form. A gift of a couple of first-class rail tickets, or the loan of a chauffeur-driven car, as is also alleged, might also seem like harmless acts of kindness.

But these are the things that could have a more direct political impact than the ghastly emotional aftermath of a failed love affair, because they are the first evidence that Mr Blunkett may have allowed his private affairs to stray into his public life.

The "evidence" should not be taken as conclusive. Though it is alleged that Mr Blunkett used his position to secure favourable treatment for his lover's nanny, he says he only advised her that she had filled in the form correctly.

He has denied outright the potentially deeply damaging story that he ordered the police to stand guard over his lover's Mayfair home to protect her against an anticipated May Day riot.

Similarly, he denied warning her parents to avoid Newark airport, in New Jersey, because of a security alert which had not then been made public.

But he admitted that he had used his position as MP to supply Mrs Fortier with a first-class rail ticket, and allowed her and her young son to travel in an official car. Use of free rail tickets are, strictly speaking, a perk only for MPs' spouses. It has already been recognised that the privilege can be stretched to include partners to whom the MP is not legally married, or gay lovers in some cases. For an unmarried MP to supply a ticket to his lover, with whom he has previously appeared in public, is unlikely to be treated as a serious breach of Commons rules.

The real damage of the latest allegations, though, is to Mr Blunkett's political reputation. He had intended to be constantly in the public eye this month - but not because of his private life.

Much of the Labour Party's next election campaign is planned to hinge on the Bills Mr Blunkett is piloting through the Commons - but after last night's developments, his no longer private life will dog him everywhere he goes.