Birmingham Yardley MP John Hemming is fathering a child with his researcher. Politics and sex have been inseparable throughout the ages, but mR Hemming may already be regretting his conduct - argues Chief Reporter Paul Dale...
John Hemming is not the first politician to be caught with his pants down. And he certainly won't be the last.
Nor is he the first intelligent man to suppose that the sanctity of marriage is an optional bolt-on extra to be adopted or dismissed at will.
And, being clever, which he undoubtedly is, I know he will forgive me for saying that, when the dust has settled and he has had time to ponder, he will concede that he has been a bit of a fool.
It is one thing for consenting adults to take a liberal view about sex, but anyone embarking on an affair must be prepared to face what is likely to happen when their unfaithfulness is revealed.
If they are in public office, the ramifications are likely to be doubly difficult.
Mr Hemming says he takes his role as a father very seriously, and there is no reason to doubt that this is the case. He is, in many respects, an exemplary parent.
This, then, must have made it all the more harrowing to explain his intimacy with his personal assistant, Emily Cox, and her pregnancy to his wife and three children, who are aged five, 12 and 14.
It is the children who had to learn about the full detail of their father's unsavoury conduct from the front pages of Birmingham newspapers.
The older children, if they chose to delve deeper, would have been able to read startling claims from their mother that their father has had as many as 26 affairs in 23 years.
John Hemming is always disarmingly honest, which is one of the more likeable if somewhat naive aspects of his character. He is never lacking in a quote for journalists, but sometimes it is better to remain silent.
There is little doubt that, because of her husband's outspokenness, Christine Hemming decided to be just as blunt.
This is what she had to say: "He started having affairs about four to five years into our marriage.
"I'm obviously distressed that he has been so unfaithful over the years and he has put me and the children in a very difficult position."
And on the subject of the pregnant Emily Cox, Mrs Hemming said: "She came round to the house about six months ago and I made it clear she was one of many and was unlikely to get him to herself."
It is a tawdry, shabby business which Mr Hemming has attempted to excuse by claiming that "few people" are always faithful to their married partners.
It is difficult to say where the evidence for such a sweeping statement comes from, but politicians can often convince themselves that right is on their side when patently it is not.
As to John Hemming's political future, there is no reason to suppose that adultery will make him a worse, or indeed better, MP than would otherwise be the case.
He has never played the family card politically or pretended to be a moral campaigner. He has never, unlike some MPs, demonised one-parent families.
He cannot, therefore, be accused of hypocrisy. Foolishness, yes, but hypocrisy, never.
Things have moved on since Cecil Parkinson was forced to quit Margaret Thatcher's cabinet in 1983 after it was revealed that his former secretary was carrying his child.
David Blunkett survived the disclosure of his affair with married publisher Kimberley Quinn. He only had to fall on his sword when it emerged he had fast-tracked a visa application for her nanny.
Paddy Ashdown, a former Liberal Democrat leader, survived when his affair with a secretary became public in 1992.
But one thing is certain: more than a few MPs will read the revelations about John Hemming knowing that their private lives, too, would not stand up to scrutiny.