May (names the) day
There was confirmation on Monday that there is no situation in which sterling might find itself that cannot be made worse by the mention of Brexit. Once again it was the prime minister who tossed the grenade when she named 29 March as the day Article 50 will be activated.
Investors learned two months ago that Article 50 would be triggered "by the end of March" and 29 March fits very neatly into that calendar slot. So Ms May's pronouncement hardly came as a surprise but investors nevertheless felt obliged to react by marking down the pound.