Boris Johnson could be relying on EU law to ensure Brexit happens on October 31st https://www.theneweuropean.co.uk/top-stories/boris-johnson-using-eu-law-for-brexit-1-6294838
The House of Lords has approved a law which would force prime minister Boris Johnson to seek a delay to Brexit if he fails to deliver a deal before October 31st. https://buff.ly/2zVXymL