So what's the latest one?
The Prime Minister, Tony Blair, has just been holding forth about "how profoundly shameful the slave trade was", in the run-up to the 200th anniversary next year of the outlawing of the practice on British ships. He didn't just praise those who fought for its abolition, but also expressed "our deep sorrow that it ever happened".
That's not exactly an apology
No, it's more an expression of regret. These historical/political apologies often are. Part of the problem is that, philosophically speaking, you can only properly apologise for something you have done. And these public statements are often on behalf of people other than the speaker, or even those he - and it's usually a bloke - represents. Mr Blair's last big public expression of regret was for English indifference to the plight of the Irish people during the potato famine of the 1840s.
No saying sorry over Iraq, then?
You're missing the point. Look at Bill Clinton. When he went to Africa he apologised for the world's inaction during the genocide in Rwanda. Not just his inaction, or Washington's, but that of the whole world. Sorry is not that hard to say when you're apologising for something someone else did. It's when we're to blame ourselves that the words tend to stick. "I did have a relationship with Miss Lewinsky that was not appropriate" and it was "a personal failure on my part". Indeed.
Where does this fashion for apology come from?
The last Pope was the real trendsetter. John Paul II apologised for no fewer than 94 things - from the Crusades, to the Inquisition, to the church's scientific obscurantism over Galileo, its oppression of women and the Holocaust. He did it throughout the 1980s and 1990s as a preparation for the new millennium. You can't heal the present, he insisted, without making amends for the past.
Everyone caught the bug. F W de Klerk apologised to the Truth and Reconciliation Commission for apartheid, or at least for the "many unacceptable things that occurred during the government of the National Party". Jacques Chirac apologised for the help the Vichy government gave the Nazis in deporting French Jews to death camps. The Japanese Prime Minister has apologised for the whole of the Second World War. And Boris Yeltsin apologised for the mistakes of the Bolshevik Revolution on its 80th anniversary in 1997.
Aren't they all just weasel words?
There is undoubtedly, shall we say, a wide range of motivation at work here. Some, such as George Bush's statements on the torture of Iraqi prisoners in Abu Ghraib - "what took place in that prison does not represent the America that I know" - may sound like an apology but they are actually a defence dressed up as condolences.
Others, like Mr Blair's latest on slavery, may well be a pre-emtive strike. By offering empathy rather than any suggestion of inherited guilt, the Prime Minister gets his retaliation in first against any attempt to suggest that Britain ought next year to be paying compensation to some group. "When we blame ourselves," as Oscar Wilde noted, "we feel that no one else has the right to blame us." Less cynically, one might observe, strategic apologies may be motivated by the speaker's attempt to change how others perceive them, or keep relationships intact.
So political apologies are just exercises in damage limitation?
They certainly risk being perceived as that. When Pope John Paul II in 1998 formally apologised for centuries of Catholic anti-Semitism and its failure to combat Nazi persecution of the Jews, many people felt he had not said enough. He made no mention of the silence of the 1940s pope, Pius XII, on the Holocaust.
Others are more forgiving. When John Paul II visited Judaism's holiest site, the Western Wall, he placed a piece of paper between the stones of the temple, as devout Jews do, which stated: "We are deeply saddened by the behaviour of those who in the course of history have caused these children of yours to suffer." No actual apology, some noted grumpily. But to many Jews, the symbolic power of the Pope's presence in that place was a more effective apology than words could ever be.
Have there been any other good apologies?
Yes, even when they didn't sound much. Often you find they are part of a process. The early apologies to the Aborigines by figures of in the Australian establishment began weakly but increased in strength over the years, and have been accompanied by some reparative actions.
You have to allow people time. In 1984 Japan's Emperor Hirohito alluded to the Second World War as "an unfortunate period in this century". It was the first step. In 1991, on the 50th anniversary of Pearl Harbour, the Japanese parliament considered apologising for the attack (but then decided not to do so).
But two years later the country's prime minister, Morihiro Hosokawa, declared the war had been "a mistake" and spoke of "a feeling of deep remorse and apologies for the fact that our country's past acts of aggression and colonial rule caused unbearable suffering and sorrow for so many people".
In Britain, too, Tony Blair's much-derided remarks on the Irish potato famine were followed, a year later, by him apologising for Bloody Sunday, in which 19 civilians were massacred in 1972 by the British Army. Not long after, the IRA made an unprecedented apology for the civilians killed in its 30 year "armed struggle". Peace dropping slowly.
How can you say sorry for something someone else did?
Many people think you can't. A lot of people in the Vatican didn't like Pope John Paul II's excessive breast-beating. One group lobbied the man who was then Rome's doctrinal watchdog, Cardinal Joseph Ratzinger, declaring that "you cannot apply a modern mentality to the actions of past centuries". Many historians agree; judging the past by the standards of the present is intellectually dishonest. We are all children of our time.
But a reluctance to square up to the wrongs of the past is often political. Many of John Paul II's critics feared that all his admissions that the church had been wrong in the past would give ammunition to critics who think it is wrong about a lot today. "As regards the sins of history," said Cardinal "Barmy" Biffi of Bologna, "would it not be better for all of us to wait for the Last Judgement?" Most people think that is a little too long a wait.
Are politicians' apologies a waste of time? Yes...
* They never apologise for things they've actually got wrong, only the mistakes of dead people, who can't answer back
* You can't judge the moral culpability of the past by the very different standards of the present
* Many politicians use apologies about the past as an excuse for inaction in the present
* They are part of a long, slow process of public healing that may begin with words and end with actions
* Change in the real world can be a long journey and the apologies can be the milestones
* Sometimes even politicians tell the truth, and from time to time they may feel genuinely sorry for the mistakes of their predecessors