For decades drivers have discovered to their cost that there is a direct link between geopolitics and pump prices, so the appointment of John Bolton as Donald Trump’s national security advisor could spell bad news for motorists.

Those with long memories will recall the oil price shock which accompanied the 1973 Yom Kippur war. Arab members of OPEC turned off the taps, imposing an export embargo.

Oil prices spiralled, soaring from $2.90/barrel to $11.65/barrel. The US imposed a 55mph speed limit and, in Britain, there was even talk about returning to petrol rationing.

Pump prices in the US have already been rising as the country moves into the driving season.

Luke Bosdet of the AA, who has kept...