It’s cold outside and starting to snow. It’s not quite the customary direction, but this year the snow seems to be travelling from Jerusalem to London, perhaps following our delightful Israeli guests, whom we are happy to welcome to our community.

I do love it when the world turns white and even London grows clean and semi-silent. Families who live only three doors apart but scarcely see one another on the average day meet with their scarves and gloves and make-shift toboggans. I have childhood memories of the Swiss mountains, and a more recent picture of how, when on the night after our wedding Nicky and I took the train to Scotland, we were greeted at dawn by a newly white world and an intrepid deer seeking food in the snow.

But right now it’s cold outside and may well be slippery. For many people it’s difficult, or plain unsafe, to go out at all. It’s a truism, but it isn’t easy to grow old, when aches and illness challenge the ready mobility which most of us take for granted and an action which would have taken thoughtless seconds requires mental planning and absorbs several minutes: How do I put on my socks? Will I be safe if I go to the garden gate?

Yesterday I was at the National Portrait Gallery with Nicky. We saw the most remarkable self-portrait: the photographer had sought to take a picture of himself in which he neither hid, nor minimised, nor emphasised the war wounds he had received in Iraq. The picture showed him perched on a kind of stool. He had no legs and had lost one arm, yet he looked calm, reflective, modest, indeed handsome, at ease with himself. How does such a person manage? How do so many people cope with so much?

On the way back home we passed a man with his sleeping bag in a corner by one of the stairways down to Leicester Square Station. I’m inconsistent, but I often give something, -though they say it’s better to donate directly to Shelter and its like, – because I don’t want a person to feel that others walk straight past as if he or she were simply invisible or somehow deemed unworthy of existence.

Outside, too, in this city now beginning to receive its blanket of snow, are all the birds and animals. From just after dawn I see the blackbirds hopping across the frozen lawn; they are ground-feeders and can’t cling to the peanut and sunflower-seed distributors which the finches, tits, and nowadays parakeets besiege. I put out a handful of raisins and hope that they will have enough calories to manage. Why should the small birds freeze to death?

Tomorrow we read about the plague of darkness. The deepest darkness, noted the Hasidic teachers, is not simply when you can’t see. It’s when you don’t see because you don’t care. The most important thing in the whole world is to care and, in some way, turn that into action.