While I cannot predict future interest rates, in my humble opinion there is practically zero chance that the ECB will raise its main refinancing rate in the next 12 months.
On balance, I would expect mortgage rates offered by our lenders to fall modestly over the course of 2016 as (a) trackers continue to be paid down; (b) default rates stabilise due to an improving labour market; and (c) competitive pressures intensify.
But, hey, I could be completely wrong!
Having said all that, if you find uncertainty particularly uncomfortable, perhaps because of your particular financial circumstances, then a fixed rate option might make well sense for you.