RE: If i knew3 May 2017 17:25
Open a CFD or spread-betting account to go short. Then your broker can explain what to do.
PS: I had it explained to me like this. You borrow shares and start off with a sell order. Say the price to sell is 100p. Then the price goes down to 90p, as you predicted. You decide to close the trade, so you buy shares at 90p, give them back (your broker does all this) and you pocket the 10p difference as profit. Et voila! and good luck.
PPS: In my view going short now is not a good idea, especially after today's news. You might want to wait and see what the next trading results are before deciding.