LONDON (AP) — The Latest on Brexit (all times local):

10 a.m.

Mounting concern among international investors about Brexit has pushed the pound to its lowest level since a "flash crash" it endured in October 2016, when uncertainty after the Brexit vote was particularly high.

The currency fell as low as $1.1960 on Tuesday, down about a cent on the day before stabilizing around $1.1990. Not counting the brief slide in the autumn of 2016, in which the currency fell around 6% in a matter of minutes before recovering, the pound is now at its lowest level since 1985.

Brexit is facing a crucial few days as lawmakers challenge Prime Minister Boris Johnson's insistence that the U.K. will leave the European Union on Oct. 31 even without a deal.

Parliament is returning from its summer recess Tuesday with a key piece of legislation on its agenda that would prevent an immediate no-deal exit. If it passes, Johnson's Downing Street office says he'll call an early election, with uncertain consequences.

8:50 a.m.

Opposition parties are challenging Prime Minister Boris Johnson's insistence that the U.K. will leave the European Union on Oct. 31 even without a deal, setting up a pivotal day in British politics.

Parliament is returning from its summer recess Tuesday with a key piece of legislation on its agenda that would prevent an immediate no-deal exit. If it passes, Johnson's Downing Street office says he'll call an early election.

A no-deal Brexit is considered dangerous because it will sever decades of seamless trade with the single market of 500 million, but Johnson insists the potential for leaving without a deal must remain as a bargaining chip in negotiations with the EU.

The bloc is adamant it will not renegotiate the agreement struck with former Prime Minister Theresa May, which Johnson considers unacceptable.