During our annual odyssey around the Scottish Highlands, I read Tears of the Rajas, Ferdinand Mount’s eloquent indictment of imperial expansionism in India. One of Ferdy’s themes is that the British lived in the country without ever attempting to make themselves of it. How far is that true of sporting visitors to Scotland? The SNP’s persecution of landowners gains traction from the fact that guests in shooting and fishing lodges encounter only keepers, gillies, stalkers. We disport ourselves within a social archipelago utterly remote from the mainland of the society in which it lies. In our defence, however, that is what tourists do everywhere in the world, much to the advantage of host nations. We must wait to discover whether Ms Sturgeon and her comrades hate tweedy foreigners so much that they will forgo our cash — and that of proprietors who spend tens of millions employing people and doing things that would otherwise become charges on the public purse.

Yet the sums paid to landowners who host windmills or build hydroelectric plants make one stutter. David Cameron has never had a credible energy policy. Billions are squandered on green nonsense, while our lights are likely to flicker in the 2020s because a cynical prime minister is heedless of the fact that only old technologies can fulfil the nation’s longer-term power needs.

This is a diary mostly about friends, because the holiday season has been spent happily among them. On Sunday I spoke at the 70th birthday party of my oldest, Nigel McNair-Scott. I not only love him and his wife Anna, but also admire them boundlessly. She has served forever on Hampshire County Council. Nigel has done many things well outside his business career, as a promoter of good causes including the Conservative party. For years he has led and helped to fund Reaction Engines, a company dedicated to creating a reusable orbital vehicle with revolutionary technology, not in pursuit of personal profit but because he wants to see Britain in space. This is no crank fantasy — engineers on both sides of the Atlantic believe the system will work given enough capital investment. Neither McNair has received the smallest public recognition, but they represent good deeds in a far better world than that of Downing Street’s recently ennobled hangers-on.

In Scotland we stayed with Henry Keswick, for many years chieftain of Jardine Matheson. He reminded me lightly that when he returned from Hong Kong and bought The Spectator in 1975, I wrote an article headlined something like ‘Taipan buys magazine to buy influence in Britain’. He has been as generous in forgiving that as he is in much else. I can make amends now, by saying that what Henry and his brother Simon have done with Jardines over a couple of generations has been one of the great British mercantile achievements of our times.

When my wife caught a salmon, a red-letter event, the talented amateur artist who was gillieing presented her with one of his watercolours. He is the son of an Indian heart surgeon, a marine biologist who prefers life on a river bank in Sutherland to southern bustle. Penny was enchanted by the unexpectedness of the man in his role in the place.

As a writer, I never cease to be moved by the support I receive from fellow historians. I gave a dinner this week for publication of my new book The Secret War, in part to thank the likes of Sir Michael Howard, Antony Beevor, Richard Aldrich, Ben Macintyre for their assistance. True, some tenured inhabitants of the great universities are fiercely defensive of their turf, and love to wage feuds, especially against non-academic historians. For the most part, however, what is astonishing is how helpful are supposed rivals to each other.

Penny and I have reached an age at which there is much discussion of friends’ ailments, some of them mortal. La Rochefoucauld’s assertion that pity is the intelligent anticipation of one’s own future troubles seems too cynical, but one knows what he meant. Other people’s Harley Street specialists are likely sooner or later to become our own, though I trust we are still a distance from the experience of Raoul Millais, who in his nineties attended a friend’s funeral. In the churchyard afterwards, a contemporary quavered, ‘Hardly worth you and I going home from here, is it, Raoul?’

We do many things better than the French, but in Normandy recently the Hastingses were touched by a sign above a disabled parking bay: ‘Si tu prends mon place prends aussi mon handicap.’