Sterling is falling again on Friday.

The pound fell off a cliff against the dollar at around 10.30 a.m. BST (5.30 a.m. ET) after a landmark legal challenge surrounding parliamentary approval of Brexit was defeated in Northern Ireland.

The Northern Irish High Court has ruled that Theresa May’s government does not need to secure the approval of parliament before triggering Britain’s exit from the European Union.

In a summary delivered at around 10:30 a.m (BST), the High Court rejected the claim that the UK government cannot use Royal Prerogative to invoke Article 50.

This caused the pound to crash, falling sharply from $1.2173 to $1.2125, a fall of almost 0.4% in a matter of minutes. It has since recovered and is now back in positive territory for the day, trading up by 0.1% from the morning’s open as of 2.55 p.m. BST (9.55 a.m. ET).

Here's the chart: