
One of No 10 chief of staff Morgan McSweeney’s favourite words is volatility. In opposition it described the vertiginous world in which Labour could go from a landslide defeat to a landslide victory in a single term. In government it captures one in which the news moves at warp speed and Donald Trump is once again US president.
As cabinet ministers look towards Washington, it is Trump’s sheer unpredictability they emphasise above all. The challenges are those that have confronted every government: when to take him literally (as well as seriously); how to determine who is speaking on his behalf (witness the drama over whether Peter Mandelson will be approved as the new US ambassador).