'That was only a ruse. What merchant takes a beautiful woman to bed in order to ask about her husband's movements in the army?'

'I see what you mean.'

'As soon as he realised what had been going on, the general knew who Daniel Rawson really was — a British spy!'

Seurel cackled. 'A lucky one at that — I wouldn't mind spying on Madame Salignac. She'd set any man's blood racing.'

'Nobody would ever get close enough to her again,' said Catto. 'The general has seen to that. His wife might as well be in a convent.'

'Mon dieu! What a terrible waste!'

Frederic Seurel made a vivid gesture with both hands to reinforce his meaning. He was a short, ugly, thickset man in his forties with dark hair and beard. He had been an accomplished thief in his youth but a harsh prison sentence had made him resolve to respect the law in future. Hardened by ten years in the French army, he had been invalided out when badly wounded in the thigh. He still walked with a pronounced limp.

Charles Catto, by contrast, was a tall, slender, lithe man in his early thirties with fair hair, a conventionally handsome face and a plausible manner. Born and brought up in England, he preferred to fight in a French regiment and it was there that he had caught the eye of General Armand Salignac. Because he was so alert, reliable and resourceful, Catto had been employed by the general in all sorts of secret missions, with an unbroken record of success. None of his assignments, however, had had the importance attached to the present one. Catto and Seurel had been left in no doubt about that.

There was a burst of activity aboard. Urged on by a stentorian voice, the crew hoisted the canvas, pulled up the gangplank, cast off and made ready to sail on the morning tide. Seurel was uneasy.

'I hate being at sea,' he said.

'Think of the benefits, Frederic.'