Each time I set out to make a film I am starting all over again. I remember the films I have made as dreams, or fugue states, too intense and painful to bear. But once they are over, all I can think about is: how do I get back there, wherever there is.

Any film begins to assemble itself long in advance, on the outer edge of an intuition. Being a director at this stage is like being a woman who is only beginning to think of becoming pregnant. It begins as a nudge, an idea of itself first, a galactic child nagging you to yank it out of oblivion.

Four years ago I went to Portbou for the first time, and remembered who had died there, and what it meant. In that strange place –narrow streets truncated by mountains or by the sea, the devouring lurid perspective of the place – a new child was born.

I wondered why his life had never been filmed.

When I first floated the idea, Joanna said: that film’s been done, intellectuals, Holocaust, Nazis shouting “Raus!” We’re living through an eruption of neo-fascism now. Shouldn’t you write a story of our times instead of treading over well-worn ground?

“Well-worn ground is the best kind of ground.”

“What kind of budget are we talking?” she snaps.

“I don’t know. Three million. Pounds,” I add, for good measure.

“Too –” Joanna’s hand flatlines just beneath her nose – her habitual gesture of the task of balancing artistic inspiration with the likelihood of financing – “low. And anyway, who would watch a film about a hapless Jewish intellectual everyone pretends to understand when actually no-one has the faintest what he was writing about?”

I would, I think. And it’s too late, in any event. He – Walter Benjamin – is already here with me, his serge overcoat, its cuffs rubbed so clean they look like coils, his copper eyes luring me into the livid dimension of the resurrected.