It will cost you £35 and sit like a brick in your luggage, but for anybody about to depart on holiday, and keen to take a book that will last for the entire break, then I wholeheartedly recommend the huge new volume of letters from the pen of Sir Isaiah Berlin – well, actually more often from his mouth, for many were recorded on a Dictaphone and later transcribed.

Enlightening: Letters 1946-1960 (Chatto & Windus) runs to 845 pages, yet the correspondence it contains represents only a small percentage of the many thousands of communications addressed by Sir Isaiah (as he became in 1957) over the period. The letters have been scrupulously edited by Henry Hardy and Jennifer Holmes, with the assistance of Serena Moore. They have not baulked at including those that show the philosopher in a less than kindly light (of which more presently), though no one reading the entire book can be other than amazed at the fecundity of his mind and the breadth of his interests.

To take but one example – music – you will find more of sound sense about composers and conductors than might be found in many specialist books on the subject. His insights on opera (he served on Covent Garden’s board during the period) are a revelation.

The book is lavishly supplied with footnotes, detailing all mentioned in the letters. One wonders whether one really needs to be told who Carl Jung, Marcel Proust, William Morris, Honore de Balzac and Thomas Carlyle are – not to mention Malvolio and Heathcliff – but the policy has clearly had to be ‘some in, all in’.

The serious minded will find all they want on such major world events as the creation of Israel (Berlin was an intimate with everyone from the first president Chaim Weizman down), the Suez Crisis and the Cold War. But those of a more frivolous bent – a hand goes up from this corner! – will delight in the gossipy, sometimes malicious, sometimes hypocritical, tone of the correspondence.

As someone who was once subjected to a half-hour lecture from the former Observer owner and editor David Astor on why we shouldn’t be beastly to Myra Hindley (no footnote required there!), I was delighted at the dissing he receives from Berlin.

Writing to an American friend in 1950, he calls him “a neurotic, muddled, complicated, politically irresponsible, unhappy adventurer, permanently resentful of somebody or something and a typical poor little rich American boy surrounded by a court of dubious toadies which gives his newspaper its queerly disoriented look”. Ouch!

There is a good pasting, too, for historian A. L. Rowse, a contemporary of Berlin’s at All Souls and the target of so many acidulous pens. Berlin tells another American pal in 1949: “Rowse grows more & more impossible & awful daily” – and then goes on to supply instances of his behaviour, “all very mad & distressing”.

Yet to the man himself, a little over two years later, he schmoozes: “I shall always be genuinely & deeply fond of you, & happy about your affection for me in which I believe: goodness me! One cannot live for 20 years on & off with someone as wonderful & unique as, if you’ll let me say so, you are & not develop a strong & permanent bond.” Yuk!

Supremely well connected socially, Berlin offers many delightful insights into the upper-class milieu. Writing to the recently Gray Matter-featured Clarissa Eden, for instance, in 1953, he passes on the verdict of the Duchess of Westminster on the social ambitions of business tycoon Charles Clore.

“Loelia when I asked if the Clores were now ‘made’ [after their big charity ball], thought not yet: 3 more parties at least needed; like a doctor in a watering place who tells a rich patient that the treatment has done him good already but 3 more visits are needed else it’s all a great waste.”

I love the story, too, recounted in a letter to Edmund Wilson, concerning Berlin’s attendance at a luncheon party given by The Queen where he “pressed the merits” to her Majesty of such unseemly works as the rampantly homosexual novels of Jean Genet, Wilson’s own sexually explicit Memoirs of Hecate and Vladimir Nabokov’s pederastic novel Lolita. “I was severely reproved for this later by the Home Secretary [Rab Butler].”

One senses, however, that the monarch may have guessed that her leg was being pulled, for she told Berlin “that her father once informed his luncheon guests that he had been reading a most interesting book – the Bible – & had any of them read it, & if so, what did they think of it”.

A smashing story from a book full of many more . . .