At West St Leonards I finally catch sight of the sky – the mixture of railway tunnels and the natural darkness till this point meant the only way I could tell if I was in the open was a cursory glance at my mobile phone signal.

A much milder start than anticipated – the weather people had warned of thick fog and a harsh frost, but perhaps that will come tomorrow morning?

I remembered to sit on the left hand side today, and the view out this way is a little more interesting as the land falls away to the left, rolling down to the sea briefly until our course is corrected to the north.

Here, the landscape is that familiar mix of agricultural land which looks somehow wild: I still remember a time before and a time after the moment I was enlightened by a friend of the fact that incredibly small amounts of the British countryside are actually ‘natural’ or wild.

Having grown up surrounded by neatly edged fields and plantations of woodland and roads splintering across the landscape, I had at one time felt that this patchwork of greens and browns was very obviously ‘nature’ in the sense of being untouched by man. It took an embarrassingly long time for me to be disabused of that impression.

Yesterday there had been a thick frost at dawn.

My weather apparatus logged a temperature of between -2 and -3 Celsius. But by the time I’d had my first coffee it had thawed as the night’s chill lost its grip, and the temperatures inverted into positive numbers.

The birds noticed this change, too. As I boiled the kettle for the first time, the garden had been empty of movement, and even the sky lacked the usual marauding seagulls and corvids. There came a tipping point, though, and by the time the tree limbs were dripping, the birds had decided en masse to wake up, and appeared to descend as one upon our garden.

I saw: wren, robin, black bird, blue tit, great tit, sparrow, coal tit, and mistle thrush – that last being an uncommon sight in this garden. I had seen previously the sparrows and tits happily sharing the same tree – the robin being more characteristically territorial, chasing off its foes – but I had not before seen this gregarious association across the species, as if a brief ceasefire had been declared on the occasion of the morning’s bitter start. For a few moments, the pecking order had been disrupted and all could pursue their first meals.

All, that is, apart from the tiny, frantic wren, whose movements had already been erratic, but as soon as the robin had become aware of its presence, it was summarily dismissed from the gathering and chased into the lower reaches of a nearby hedge. Some rivalries persist even during the harshest hours.