‘Roberto,’ she said. ‘Do you think you could take me back to the Hassler? Being twenty-one has aged me suddenly. Or perhaps it’s just that I’ve drunk at least three bottles of champagne all by myself. I could take a taxi, if you’ll order one. I’m sorry, Roberto. Really I am.’

‘It’s not possible,’ he said, laughing at her. ‘I am going to take you to a party at a friend’s house. You will wake up there, and feel wonderful again. You cannot go to bed now, on your birthday, like an old lady.’

The room of the ancient palazzo was heaving with young people dressed in the extravagant finery of affluent Roman society. Roberto introduced her to their host. She did not catch his full name above the noise of the party, but he was a prince of some kind. All around her there was music and dancing and couples lying on velvet sofas, locked together and kissing, drinking champagne and small shots of liqueurs, smoking marijuana and popping brightly coloured pills from little gold and enamelled boxes.

‘I can’t stay long, Roberto,’ she said. ‘I really am wilting now.’

The prince was standing at her elbow. ‘Ah, but you have arrived just as we are serving dessert,’ he said. ‘Drink some champagne, and I will bring you something that will make you forget you were ever tired.’ He signalled to a waiter who offered a tray laden with tiny, glistening cubes of sugar, and dropped one into her glass.

Camilla looked at him as he walked away. Then she raised her glass to Roberto and smiled as she drank the cocktail. He beckoned her into the centre of the room and she danced with him, following his slow movements, allowing him to hold her very close, until her fingers began to tingle and she realised she was dizzy. When there was a break in the music she disengaged herself and moved to the window of the palazzo, to breathe in the night air and to look down into an ancient square with a fountain. Roberto followed her, whispering something in her ear that she did not catch. Below her the fountain suddenly leapt high into the air, the jets of water shooting upwards in a series of brilliant colours and shapes, turning into huge, iridescent flying fish. She gasped in surprise and turned back to the room where the walls were moving in and out, exploding with colour and force, heaving with each breath she took. People were gliding past her, indescribably beautiful, so that she wanted to reach out and touch them. The music melted into bright colours that flowed like streamers, and she could taste each note of the saxophone, feel every beat of the drum deep in her stomach.

‘Acid?’ She looked at Roberto, saw his eyes shining like dark pools, his mouth cherry red and glistening. ‘Oh God. I’ve never done this.’