FTSE to rise or fall due to brexit?

TVC:UKX   UK 100 Index
With in a 52wk range there has been a high of 4,993,89-7,585,98 on index value. with it on a negative slope, working out if it will fall below the index value of 6400,0 as of previous events brings me uncertainty. With the average constituent size of 15,010 and the highest being of 109,418. Buy or sell ???