Although the diplomatic situation was still grave there was some good news. A peace had been agreed between Britain and the United States. That, Arthur was reassured, would mean that the government’s attention could focus on Europe. It would also mean that more soldiers would be available for deployment in the army under Arthur’s command in the Netherlands.

Christmas passed peacefully and Arthur and Kitty did their best to entertain the two boys by showing them the sights of the French capital. Even as he tried his best to play the role of a dutiful father, Arthur’s mind was distracted by the burdens of wider affairs. He had urged the French King to order Talleyrand to co-operate with Castlereagh in Vienna, and early in the new year a secret treaty was signed, binding Britain, France and Austria in a pact against the other two powers if war broke out.

Arthur left Paris in the last week of January, travelling by carriage to Vienna where he arrived on the evening of 3 February. Despite the late hour he sought out Castlereagh at the fine mansion that had been allotted to the English representatives at the Congress. Castlereagh looked grey and exhausted when Arthur was shown into his study by a servant. The other man rose, smiled wearily and came across the room to take Arthur’s hand.

‘Good to see you again, Arthur. How was the journey?’

‘Long and wet.’

‘Loquacious as ever,’ Castlereagh chuckled. ‘Still, reticence will serve you well here in Vienna. Despite civilised appearances - there seems to be a ball, banquet or ballet happening almost every hour of the day - the place is a nest of vipers.’

‘So I gathered from your letters.’

‘Talleyrand and Metternich are the most devious scoundrels I have ever encountered, forever doing the rounds of private salons and offices proposing secret deals and selling confidences. Why, they have turned such practices into a virtual industry. I suppose I should be grateful at least that they happen to be “our” scoundrels. At least for the present.’

‘I take it that you have had to offer them disbursements to support our position?’ Arthur asked as he sat down. Castlereagh resumed his seat and nodded.

‘I probably did not need to have offered such inducements, but the situation is such that I was not prepared to take the risk. Now that we have the treaty signed and sealed, I hope that you will not have to pay them another penny.’ Castlereagh smiled faintly. ‘I know you have a pronounced distaste for bribes and back room chicanery.’

‘That is right,’ Arthur replied firmly. ‘I believe that men of honour can achieve more lasting good through being patient and observant than through politicking.’