A sudden BREXIT on 1 April 2019 is highly unlikely, because more or less impossible. Jeremy Corbyn is unlikely to succeed in his Vote of No Confidence tomorrow 16 Jan 2019, and his leadership of British Labour becomes shaky. Theresa May will continue in office and some arrangement for a Slow Brexit will ensue: perhaps a postponement of the date, perhaps another referendum, perhaps an agreement that Brexit is noted to have happened, but all present trading arrangements remain in place until altered. So, we can bet that Sterling has now reached the bottom (or dip a little more for a day or two) and will start its rise quite soon, as it becomes apparent that BREXIT ON APRIL FOOL'S DAY is notional rather than real.