The UK High Court ruled that Parliament has the right to vote on Brexit for Article 50 is triggered. Sterling had appreciated for four consecutive sessions coming into today. It was trading near $1.2350 in anticipation of the decision and rallied to $1.2450 before running out of steam shy of the post-flash crash high (~$1.2470).
As expected the government quickly said it will appeal the ruling to the Supreme Court. That the losing side would appeal the decision was widely known and the Supreme Court made room in its calendar for just this eventuality.
The $1.2450 area corresponds with a 38.2% retracement of sterling’s decline from since early-September. Sterling has also stopped short of the two-month trendline, shown in the Great Graphic that was created on Bloomberg. The 50% retracement is near $1.2640, which is a little above the high before the flash crash (~$1.2620).