The British government said in court papers that Boris Johnson would send Brussels a letter asking to delay Brexit if he did not secure a new deal by later this month https://nyti.ms/2o5zhs6
Government tells Scottish court Boris Johnson will send Brexit extension letter if no deal is agreed by October 19th. https://www.theneweuropean.co.uk/top-stories/scotland-article-50-brexit-extension-court-case-1-6306435