‘Pacta sunt servanda,’ said Bertie. ‘I read all about it, Daddy. It’s a principle of international law. It means that you must keep your word.’ He thought of Tofu. Tofu needed to have this rule explained to him. And Olive too. And Hiawatha, who had recently promised Bertie to give him a packet of crisps in exchange for a peanut-butter sandwich and had then reneged on the agreement on the grounds that he had been crossing his fingers at the time.

Stuart nodded.

‘What is international law, Daddy?’ asked Bertie.

Stuart raised an eyebrow. ‘It is, I believe, the system of rules that countries have to obey.’

Bertie thought of this. ‘And do they?’ he asked.

‘When it suits them,’ said Stuart. ‘Otherwise no. Otherwise they say that the rules are all a bit vague.’

‘I see,’ said Bertie. He was now thinking about fishing. ‘Where will we go?’

‘We’ll try one of those lochs up there,’ said Stuart, pointing vaguely in the direction of the Pentlands. ‘I can borrow a couple of rods from somebody round the corner. I know a man who’s got all the necessary stuff, Bertie.’

Bertie moved from foot to foot with excitement and pleasure. ‘And can we have sandwiches, Daddy?’

‘Yes,’ said Stuart. ‘We’ll take sandwiches. And I’ll buy some crisps from that garage opposite the ski slope. They have lots of crisps there, Bertie.’

Bertie closed his eyes in sheer pleasure at the thought. And when he opened them, there was his mother, who had been in the kitchen when this conversation with his father had begun.

‘What’s all this, Stuart?’ Irene asked. ‘What’s this about crisps?’

Stuart swallowed hard. Bertie noticed this, and looked away.

‘Bertie and I …’ Stuart faltered. Bertie felt his heart miss a beat within him.

Irene kept her eyes on Stuart. ‘Yes?’

‘We’re going fishing, Mummy,’ Bertie blurted out. ‘We’re going fishing in one of those lochs in the Pentlands. Daddy’s going to get some crisps so that we can eat them while we’re …’ Now he, too, faltered. But he plucked up his courage. ‘Tomorrow.’

‘Tomorrow?’ said Irene. ‘But tomorrow’s a school day, Stuart. Bertie can’t …’

Stuart closed his eyes. ‘Decision taken!’ he said firmly. ‘No school for Bertie tomorrow. Fishing. All decided!’

Bertie looked at his father in sheer admiration. Then he looked at his mother. Her eyes were narrowed.

‘Stuart,’ she said quietly. ‘A little word with you in the kitchen, if you don’t mind.’

Bertie held his breath.

‘No need,’ said Stuart breezily. ‘It’s all settled. I’ve told Bertie it’s all fixed up. End of story.’

‘Yes,’ said Bertie. ‘Pacta sunt servanda, Mummy.’

Two against one, thought Bertie. Two against one. No, three, if you counted Ulysses.

67. An Outing Begins