‘No idea exactly what they do,’ Nell giggled. ‘But I think it involves formaldehyde.’

‘Isn’t that what they preserve your appendix in?’ Penny asked. Colin had kept his proudly on top of the telly until Wendy knocked it over accidentally-on-purpose when she was fifteen.

‘The very same.’

‘Goodness!’

No more conversation about hair treatments was possible, as young Andros had nimbly threaded the mooring rope through the hole in the nearest rock. Then he and Nikos helped them down into the small blow-up boat they had been towing behind them.

‘We had one of these when we went on holiday to Devon,’ Nell informed them. ‘Me and my brother had to blow it up with a bicycle pump. It took hours!’

‘I’m glad you and your brother didn’t blow up this one,’ Dora remarked, stepping into it gingerly.

‘Thank God you’ve given up those stupid stilettos,’ remarked Moira.

‘Yes,’ Dora grinned. ‘I am now the proud owner of a pair of plimsolls.’ She flashed her foot at them.

‘My God, look at that!’ Penny pointed at the water over the rock formation many feet below as they approached the entrance of the first cave. ‘It’s like an impressionist painting!’ They all stared down. The water was a blaze of not just blue but green, bright turquoise, yellow and even rusty red.

‘It’s because of the minerals in the rocks underneath,’ Nikos explained. He steered the boat through a natural arch in the rock and they found themselves in a vast cathedral-like cave, with other smaller natural chambers leading off it. At the far end was another arch leading back out into the bright sunlight of the Aegean.

‘That was why it was a favourite with the pirates,’ Nikos explained. ‘They had an escape route. They could get straight out to sea through that arch. They would rob the Turkish, or sometimes the British ships, and hide their spoils here. They didn’t rob the French ships because they came from France themselves. That was why they were allowed to get away with it. Until, in the seventeenth century, the king of France decided they were too much of a risk and started hanging them.’

But Dora wasn’t listening. She felt her heart speeding up and found she was unconsciously holding her breath. She was holding her iPhone as if to take a photograph and had surreptitiously put on the light instead. As she directed it into the second cave, she thought she could see something that had been stashed there.

Silently, Dora pondered what to do. She’d always hated water. The very idea of scuba diving made her feel like being stuck in a lift.

Of course, she was probably wrong, and she would look very stupid if she made the suggestion that Xan Georgiades had found the Venus and hidden it here.

She would have to look more closely.