The SNPs call for another independence referendum was always going to be inevitable following the result of the EU referendum. In the first independence referendum, the argument was propagated that leaving the UK would cause Scotland to also leave the EU. Consequently as the UK government, campaigning to maintain the union, used this argument, it is hardly surprising that the SNP now seek another referendum.
While the UK government may wish to postpone a referendum beyond Brexit I suspect that this will prove impossible. Consequently the fight to maintain the UK as part of IndyRef2 will become the defining of the new post Brexit UK. That is how the next Scottish independence referendum has to be fought. This is therefore an opportunity for the UK government to propose a new frame work for the UK, an exciting vision for what the UK will be post brexit.
Winning a NO again in a second Scottish referendum would allow the UK government to push forward with Brexit knowing that the most hostile region to Brexit has been persuade. A partial mandate for the new look, post brexit UK.
Losing the referendum sees the SNP removed from Westminster which hands the current government a more robust majority which may be of use to complete the brexit process.
Indyref2 was always inevitable, it being called now can be a great opportunity for the entire UK.