Jeremy Warner

Donald Trump was a good deal more candid than we have come to expect from this otherwise most vainglorious of US presidents in announcing last week’s memorandum of understanding with Iran.

It's called killing the goose that laid the golden egg, and there is a high chance that Andy Burnham, Britain's prime-minister-in-waiting, is about to make precisely this mistake.

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Look after the present and the future will take care of itself. This ancient piece of handed-down wisdom can be read two ways.

Nostalgia. Ah, that gloriously intoxicating longing for the warm glow of an imagined past that never really existed.

Few British prime ministers have had such a meteoric rise as Andy Burnham, whose unchallenged ascent to Downing Street was confirmed on Monday.

It's been described as the largest disruption in oil supply in modern history – bigger even than those of the 1970s . And it's been going on for four and a half months now.

John Healey as Chancellor, Ed Miliband out as Energy Secretary and a minor tax cut as a down payment on the promise of more to come.

Andy Burnham is discovering how different being Greater Manchester mayor is from life in No 10 - Nicola Tree/Getty Images Europe

It was the pledge that cost Theresa May her majority , and ultimately her job as prime minister.