‘But come in for a cup of coffee before you go,’ he’d said. ‘I hope it might make the dog settle better than when you just drop her off at my front door.’

So we did that, and I took Rosie’s usual bed along with me so she would feel more comfortable, placing it in Charles’s kitchen next to his Aga, in the same manner as it was at home.

‘Did you have a good dinner?’ I asked.

‘Excellent,’ he said. ‘The only trouble is that most of the admirals I served with have now fallen off the perch. Only young chaps these days, some of whom didn’t join the service until long after I had retired. But it was fun nevertheless, and it was good to spend a night in London. I even walked up to Jermyn Street yesterday morning and bought myself some new shirts.’

He poured coffee into three mugs and carried them over to the table.

‘So who is this Kaiser chappie?’ Chico asked him.

‘The Kaiser?’ Charles said.

‘Sherlock Holmes, here, says he’s helpin’ us.’

‘That isn’t quite what I said.’

‘Kaiser Wilhelm II?’ Charles asked.

I nodded.

Charles stared first at me, then at Chico, who looked back at him with an expectant expression. ‘Sid said you would know him.’

‘He was the last German emperor. Kaiser is the German word for emperor. It was he who started the First World War.’

‘I thought it was because someone was assassinated,’ I said.

Charles nodded. ‘That’s what the history books will tell you. Archduke Franz Ferdinand, heir to the Austro-Hungarian Empire. He was shot dead during a visit to Sarajevo, causing the Austrians to declare war on Serbia. That caused the whole international diplomatic house of cards to collapse due to various military alliances, but it was the Kaiser who really wanted the war, and he made sure it happened.

‘When he became German emperor on the death of his father in the 1880s, he sacked all the politicians and assumed total control, building a huge army and a massive navy in order to threaten all his neighbours. He was absolutely itching for a war. Dreadful man. He also wore an appallingly stupid moustache.’

That was clearly, in Charles’s eyes, almost as damning as having caused a world war. After all, moustaches on their own are not permitted in the Royal Navy—British sailors either have to be clean-shaven, or have a full set: a moustache together with a beard.

‘But I suppose we should be grateful,’ he said.

‘Grateful? Why?’

‘Grateful that he wasn’t also the king of England.’

‘You mean because Germany lost the war?’