The burly Magyar ignored Goodenough and snapped some orders in Hungarian. A group of his men hurried below decks.

‘You have two choices.’ Zoltan approached Goodenough. ‘You can tell me the combination of your safe, or I can cut it out of your pretty boat with axes.’

Once again Louis stepped forward and in a quick, expert movement Zoltan pulled a small pistol from inside his tunic and levelled it at him.

Goodenough recognised the pistol: it was an Italian navy-issue 9-millimetre Beretta. These men were no scruffy, disorganized opportunists: they were serious professionals.

He quickly gave the combination for the safe and Zoltan shouted another order to his men.

In a moment there were screams from below and Grace Wainwright was dragged on to the deck. She was followed by the pale-skinned sailor carrying the contents of the safe. Zoltan looked from Grace to the haul, then shook his head peevishly and rubbed a temple.

There was a deep, guttural grunt and the tattooed giant tossed something across the deck. Zoltan caught it and his face brightened.

It was a small bronze statuette.

‘Thank you, Tree-Trunk,’ he said.

Tree-Trunk smiled and exhaled a cloud of cigar smoke.

Zoltan held the statuette up to his mouth with two hands and kissed it.

‘Leave that!’ yelled Goodenough, his anger getting the better of him. ‘That will be of no value to you. It is a very well-documented piece of art. There is nowhere in the world you could sell it… And if you melted it down it would be an absolute tragedy.’

Zoltan smiled, turned slowly and fixed Goodenough with his steel-rimmed gaze. ‘I am not a peasant!’ he said. ‘I am no ignorant gulyás. I know what I want. I want this bronze, Sir Cattle.’

‘Cahill, man – it’s Car-hill!’

‘Be quiet, you damned Englishman.’

‘You know nothing of its true worth,’ Goodenough protested.

‘I know it is by Donato di Betto Bardi,’ said Zoltan. ‘Commonly known as Donatello. Fifteenth century, cast in Florence, a model for the design of a fountain that was never built.’ He turned the statuette in his hands. ‘It is a figure from Greek mythology. A siren. The very siren that this boat was named after. The sirens were monsters – half woman, half bird. With their beautiful voices they tricked passing ships on to the rocks and ate their crews.’ He looked at Goodenough. ‘Women, Sir Goodenough. You must always be careful of them. They are dangerous.’

‘That statuette belonged to my wife,’ Goodenough said quietly.

‘This statuette was stolen by Napoleon from the Duke of Florence,’ said Zoltan. ‘And it was stolen from Napoleon by one of your wife’s family after Waterloo. Now it is my turn to steal it.’

Goodenough made a grab for the bronze and the Magyar flicked a hand at him, as casually as if he was swatting away a fly, but it was enough to send Goodenough crashing to the deck. He lay there for a moment, stunned.