When my uncle Victor in Madrid picked up the phone on Thursday morning, there was a weariness in his voice that I had never heard before. It was just a few hours after first news broke of the atrocities in the Spanish capital and he’d probably fielded a string of calls already. But maybe this straight-backed broad-shouldered 85-year-old was betraying a longer-term fatigue.

Victor’s bearing tells you that he spent his life in the army. He witnessed appalling loss of life during the Spanish civil war. His family was divided by that conflict. One of his brothers perished, and another — my father Luis — fought for the defeated republicans and departed for exile in England. Spain has put aside the passions that set brother against brother.

But since democracy was restored in the 1970s, bombings and murders by Eta terrorists have been frequent.

The only television pictures were coming from Atocha station, showing the red train ripped apart by explosions. Many tourists will have used those lines for a day trip to Toledo, or passed through the station to catch the high-speed train to Seville.

When a few years ago I made a film of a railway journey through Spain (a sort of television biography of my father) I dwelt on the beauty of the station. It outgrew the 19th-century canopy of iron and glass, so they built platforms beyond, and converted the old station into a tropical forest of high swaying palms. It serves as an arboreal anteroom for passengers hurrying across the marbled flooring towards their trains. Cloudbursts of water droplets maintain the humidity needed for the lush vegetation.

On Thursday I struggled to imagine that beautiful spot brutally converted to a triage station where the wounded dragged from the wreckage could be sorted according to the severity of their injuries, a bustle of doctors, nurses, firemen, nuns and priests.

I have 28 Spanish first cousins in Spain, many with large families, and I was anxious for them. As far as I know the whole clan is safe. I thought of them again on Friday night, taking to the streets of Madrid, and Salamanca where others live, united in defiance against barbarism.

In London I clustered with a few score Spaniards who live in England under the entrance canopy of the Spanish embassy, in a vigil timed to coincide with the multitudinous gatherings in Spain.

A young girl stood on the steps and said in Spanish: “We’ll have a minute’s silence”; and I stood staring down at the bouquets of flowers piled high by the embassy’s front door, thinking about all the brothers and sisters and fathers and mothers slaughtered on their way to work. When the minute was over we clapped. Goodness knows why. Perhaps we had to mark the silence’s end with noise and none of us could be sure of getting a sound out from our dry and gagging throats.

A young man said to me that he was proud to see me there with them. I couldn’t produce a reply so I clapped him mutely on his leather-jacketed shoulder, feeling that was probably what Spaniards do.

Terrorism has been the curse of a country that has otherwise lived a charmed existence since the 1970s. Few countries emerging from dictatorship have shrugged off their past with so little recrimination. When General Franco, who had taken power during the civil war in the 1930s, died in 1975, there were no reprisals and no war crimes trials. The Spanish people unanimously moved on. The monarchy rather than a republic was restored, against my father’s wishes, and Spain lost Franco’ s grip on law and order and public morality, to my uncle Victor’s disappointment.

Spain faced a particular problem with its regions. Franco had fought to keep Spain united and centralised, repressing local languages and flags in Catalonia and the Basque country.

The constitution devised in the 1970s gives the regions substantial autonomy. In the Basque country the road signs are bilingual and nationalist colours are everywhere on display. The British branch of the Portillo family has many Basque friends, not least because my parents met in England, looking after Basque refugee children. They had been evacuated after the attack on Guernica in 1937, when more than 2,000 civilians died, bombed and strafed by German planes.