Boris Johnson’s determination that the UK will leave the EU on 31 October “no matter what” has seen sterling drop around 2.5% since he became prime minister last week, reaching lows last seen in the wake of the EU referendum in 2016.

Quilter Investors’ Hinesh Patel says: “Financial markets have woken up to the scare of a hard Brexit this Halloween. But the ‘Brexit risk premium’ in sterling is mostly baked-in – today, the currency’s destiny hinges on central bank actions.

“If the BoE ‘out-doves’ the ECB, Fed and BoJ then sterling tests $1.20 – and presumably this would happen because the economy is about to fall off a cliff. In that situation you can throw out your calculator for FX conversions because it’ll be €1/$1 to the not so great British pound.”