The pound has risen in value against the dollar after the Supreme Court ruled Boris Johnson's suspension of Parliament was unlawful.
A unanimous ruling by the Supreme Court found Mr Johnson's prorogation of Parliament until mid-October was unlawful.
Speaker of the House of Commons John Bercow reacted to the decision by saying Parliament "must convene without delay".
The pound rose in the wake of the decision, but the markets quickly settled back as traders assessed the lingering uncertainty, Bloomberg reports.
Craig Erlam, senior market analyst at Oanda, said: "It's extremely difficult to say whether the ruling will be a game-changer or nothing more than a headline maker but it will certainly ramp up the Brexit theatrics, just over five weeks ahead of the end of October deadline.
"Sterling is probably an accurate reflection of the news, with it initially spiking on the defeat for Johnson's pro-no deal government, before settling back around pre-ruling levels."
The pound at 12pm today was 1.2446 dollars compared to 1.2488 dollars at the previous close.
At 10am this morning the pound was 1.2436 dollars compared to 1.2488 dollars at the previous close.
Sterling rallied and the FTSE 100 fell to a day low as is typical for any news that eases worries about a no-deal Brexit.
Investors now have to wait for the government to respond.
The midcap FTSE 250 didn't benefit from the rise in the sterling, which highlights the level of disquiet in the market.
David Madden, market analyst at CMC Markets UK, said: "I think the downward move in the FTSE 250 is due more political uncertainty, the chatter of a general election is going the rounds, which has chipped away at equity market sentiment."
The FTSE 100 is now down 0.1% and FTSE 250 is down 0.3%.
Labour leader Jeremy Corbyn is calling on the Prime Minister to announce another election, saying Mr Johnson must "consider his position".
Mr Johnson is currently in New York, attending the UN.
