The Prime Minister has set a schedule for his resignation, the opposition is in disarray, and Scotland is proposing revolt. That, unfortunately, isn't exactly a formula that suggests a stable future for the country in the short-term. It's hard to not expect at least some reaction to that.
I think 'volatile' might be the best description of the market, there are far too many factors at play.
For example, if companies are rumoured to move their business out of the UK, it might boost the FTSE. Similarly, if the currency falls, the FTSE would also appear to do better (from a UK perspective).
I certainly wouldn't like to bet on what happens tomorrow.