It’s a mercy mission. I have him talking about his wife, Sarah. ‘Go on,’ I say, but his eyes are shut. He’s gone off air. ‘I have no words,’ I tell him.

‘No words...’ he repeats... from the far side of the universe.

‘Don’t think about it now,’ I tell him. ‘You’ll hurt your head. Thinking is a physical act.’

‘I think I’m finished,’ he whispers.

I leave a silence. Then I say: ‘There’s a bag of crisps in the glove compartment, if you would like them...’

When we get the narrow boat going it makes a soft chugging. ‘Listen to that,’ I say, trying to express satisfaction. Then I say: ‘Listen to those birds, Robbie. I can see he is listening, but perhaps what he hears in the sound of a ventilator.

‘The human race will expire not in a great nuclear explosion,’ he says, ‘but to the sound of birdsong.’

‘We’re not talking about it,’ I insist. ‘We need to hold our nerve in the face of all of this.’ My hand is on the tiller. He reaches out and squeezes my wrist. ‘That smell I got in the car,’ I say, ‘its Sarah’s perfume?’

Yes. Just a little - to remind him. He never liked it much.

‘And she wouldn’t like this,’ I say. ‘We know that. Cranking locks, galley fry-ups, going nowhere in particular.’ He agrees.

‘I’d prefer to be out walking. We liked to walk.’

‘We’re travelling at walking speed,’ I say. ‘Wild, isn’t it?’ Robbie ...