From a gallery, hidden by a great tapestry, a small orchestra struck up the Spanish national anthem and Napoleon began to introduce his senior officers and officials to Charles and his wife.

Later, when night had fallen outside and all the guests had long since departed from the ballroom, Napoleon met Charles and Fouché in a small private sitting room with doors and windows that overlooked the geometrically perfect flowerbeds of the château’s garden. His sister Caroline, together with the wives of some of the generals, had led Marie-Louise off to a picturesque orangery in the grounds to be entertained by an opera singer from Paris, while Napoleon dealt with Charles alone.

‘I must say, it is most good of you to step in to sort this ghastly business out,’ Charles began affably. ‘You’re not quite the tyrant that some of your enemies make you out to be.’

‘Really? That is good to know.’ Napoleon smiled warmly. ‘It is a shame that there are those who mistake my motives. But who can blame them, with all the lies that are spread by British agents?’

Charles frowned. ‘I have to confess that my own son was easily misled by such devils. Truly, the British will stop at nothing to undermine every royal house in Europe.’

‘Sadly, you are right,’ Napoleon said solemnly. ‘And the Spanish Bourbons are no exception.Why, when I spoke to your son, he was little more than a mouthpiece for Britain, and damned your alliance with France as the work of a fool and a madman.’

Charles’s eyes narrowed. ‘He said that? Of me?’

Napoleon nodded with a pained expression. ‘I wish it was not true, but . . .’ He gestured helplessly, and watched as his words worked their way on the weak-minded Spanish ruler.

Charles’s lips trembled with rage as his jaws worked furiously. ‘That damned boy! Always was ambitious, and treacherous as a snake. To turn on his own father. And his King!’ Charles fixed his watery eyes on Napoleon. ‘He must not be allowed to be King. I will not permit it.’

‘Ah, you see, there’s the problem,’ Napoleon responded with feigned embarrassment.

Charles frowned. ‘Problem? What do you mean?’

‘Well, I don’t mean to sound defeatist. As far as France is concerned you are the King of Spain.Those others who forced you to abdicate are clearly traitors.The problem is that they have managed to persuade most of your people to believe their lies. I fear it may already be too late to undo such villainy.’

‘Too late?’ Charles looked pained. ‘But I must have my crown back. For the good of my people.’

‘Naturally. But the reality of the moment is that it would not be good for your people if you were to return to the throne. Later, perhaps, when Spain has had the opportunity to forget these troubled times.’