Sterling rout also means slide in Irish bank shares

In the coming days, markets may probe and call the bluff on Boris Johnson's threat to crash Britain out of the EU, setting up a full-blown currency crisis well before the Brexit deadline he has set to get out with or without a transition deal by Halloween.

The political game of chicken his weak administration is playing with the EU may turn into something else -- a political and economic crisis with currency markets testing which of the two blinks first. Sterling hurtling to new lows against the dollar and towards parity at 100 pence against the euro is something Mr Johnson and his jittery DUP just cannot ignore.