But while Ignatieff is not blind to the inconsistencies of Berlin's philosophy, his affection for the man, and empathy for his ideas, constrains his ability to explore its more problematic aspects. Yet, as his interview with Steven Lukes reveals, Berlin's liberalism was highly ambiguous. The defence of pluralism all too easily gave way to a desire to exclude minorities. A cynic might argue that the difference between Eliot and Berlin was less about whether minorities should be put "beyond the borders of the city" than about which minorities should be so excluded.There are few people better equipped to chew over these problems than Michael Ignatieff.

it is quite natural that each side should think that they cannot lead free lives in an integrated society if the others are there in quantity." Black immigration to Western Europe was "a problem" because "cultures which have grown up with no contact with one another have now collided". Was it possible, Lukes asked, for peoples of different cultures, such as Arabs and Jews, to live together? "When you have two peoples of different origins and cultures," Berlin replied, "it is difficult for them to live together in peace ... The diary shows clearly that all three essential ingredients are missing.The company is still capable of fine work (the recent Ring in London and Birmingham is proof of that), but most of the people who run it have lost the confidence of their artists, the loyalty of their audience, and the ear of the government. I don't believe the Royal Opera House will reopen for years..

Isaiah Berlin by Michael Ignatieff Chatto pounds 20 In the autumn of 1951 wrote an essay in the Jewish Chronicle putting the case for Zionism. Until the founding of Israel, he observed, no Jew had been free to live a purely Jewish life, free from scrutiny and repression. Berlin was particularly scathing about Gentile intellectuals, such as T S Eliot, those "souls filled with terror" who feared that a Jewish presence undermined Christian civilisation.When Eliot protested that he was no anti- Semite, Berlin was sharp in his rebuke. "Am I profoundly mistaken," he wrote to Eliot, "that you thought it a pity that large groups of 'free thinking Jews' should complicate the lives of otherwise fairly homogenous Anglo-Saxon Christian communities? and that it were better otherwise? and that if this could be done by humane means, and persuasion and without coercion, it would be better for such communities if their Jewish neighbours, or a sufficiently large proportion of them, were put 'beyond the borders of the city?'"Forty years later Berlin was interviewed by the political philosopher Steven Lukes. It staggers under the news of Bernard Haitink's resignation, and of Vivien Duffield's threat to close her purse (made as early as 8 September 1997, according to Allen). Yet the huge redevelopment in Covent Garden requires remarkable administrative skill, great artistic sensitivity, and pots of money. The idea then was to perform in the Lyceum instead, even if that meant paying a penalty for reneging on the Sadler's Wells deal.Mary Allen's diary convinces me that the Royal Opera House must be close to self-destruction.

On one occasion when the television had put her to sleep, Nigel had brought a duvet and put it over her; then he brought another duvet so that he could lie on the floor beside her. He never complains when the car disappears or when she breaks down while they are eating the Christmas goose.We learn plenty about the insecurity and vulnerability of this proud, confrontational woman. Despite having served as secretary general of the Arts Council, she is out of her depth at the Royal Opera House. The politics are too slippery, the black hole into which money disappears is too huge. The Board incapable of keeping its hands off, and the interests of artists running the opera and ballet conflict with the strategies of the administrators.Worse - there is something about the place that encourages irrational fantasy. For example, we learn that the act of treachery that extinguished the Royal Opera and Ballet season at Sadler's Wells next year was being seriously contemplated by Allen last January, nine months before the bombshell exploded. I believed her.)The diary's only consistently nice character seems to be Mary Allen's husband, Nigel.

When she can no longer sleep through the night, she falls asleep at dinner and on the underground and on the sofa. One of the many occasions on which Allen bursts into tears is at rumour that she only got the job in the first place because she and Chadlington were lovers. (When I asked about this - in a round-about way - she replied robustly that he was not sexy enough. Following the breakdown of the Warren-King partnership, King's lawyers went to the High Court earlier this year and had pounds 3.35m of Warren's personal assets frozen. King is suing Warren for megabucks and the case does not come to court until January.