‘Yes, yes, of course he did,’ Johnson agreed with a hearty nod and a salutary wave of his hand, ‘and most nobly. My active service was limited to the one mission only, but the truth is, on this particular occasion I was ordered to Australia for a purpose far broader than combat duty. A purpose that remains secret to this very day,’ he added, tapping a forefinger to the side of his nose in classic conspiratorial manner and even lowering his voice, although there was not a soul within earshot. ‘And there’s a certain synchronicity between that purpose and the toast we just made to the Civil Rights Act. Which is why I decided to open my bottle of Bundaberg and share my story with you, Robert.’

Bobby was now very much intrigued. It appeared Lyndon was not about to boast of his citation and his dubious war record, but something altogether different.

As Johnson raised his glass, Bobby followed suit and both men took a further sip of their rum, acknowledging this rare moment of camaraderie.

‘I was called into this office when I was several years younger than you are right now,’ Johnson went on to explain. ‘The year was 1942 and I was to receive orders directly from President Roosevelt. General Eisenhower was also present, just the three of us. That was actually the first day I’d met Ike. He was here in the Oval Office when I arrived and FDR introduced us personally, quite an honour. As you would well know,’ he added, ‘Eisenhower was coordinating the Pacific War strategy from our end while MacArthur was commanding the forces in the field.’

Johnson gave a smile that was intended to be a mix of humility and self-deprecation, neither of which worked. ‘As a young congressman, you can well imagine I was somewhat overawed at finding myself alone in the company of FDR and Ike.’

He hadn’t been overawed at all. He’d recognised the magnitude of the moment for exactly what it was – a God-given opportunity for the advancement of his career. The young Lyndon Baines Johnson’s ambition had been boundless.

And I was proved right, wasn’t I, he now reflected with pride. Just to think, three US presidents together, here in this very room! Well, two of us didn’t know at the time we were destined for presidency, he told himself a little smugly, but in hindsight the memory of us three together sure as hell is impressive.

Lyndon could recall every moment of that meeting with vivid clarity.

‘I have a job for you, Congressman,’ Franklin D. Roosevelt had said, wheeling his chair out from behind the desk and gesturing for the other two to sit, which they did.