GBP/USD jumps to a high of 1.2788 on the headline but settles down now
The jump sees cable move towards the 100-hour MA (red line) as well as the resistance region around 1.2777 but price is starting to fall a bit short in breaking above that now. If anything, this looks more like a jump that is destined to be faded.
Although the ECJ may rule in favour of allowing Article 50 to be revoked unilaterally (without the need to consult other countries), this is an option that will almost certainly not be taken by the UK government as they are still in favour of respecting the results of the Brexit referendum.
All this does is present a tiny hope of a possible no Brexit option, which isn't likely to be triggered at this point. You can't rule out anything in politics but let's call a spade a spade. This isn't going to change things ahead of the meaningful vote next week.
Unless pound buyers gather some newly-found determination for price to break above the 200-hour MA (blue line), expect the jump here to be short-lived. However, even in the event of a decent move higher here I would still expect the similar mood to play out as it has over the past week-and-a-half: sell any decent rallies in the pound.