The Economist asks
Between 21 November 2017 and 30 September 2018, how will S&P next adjust the United Kingdom's long-term issuer credit rating?
Revisions to the "outlook" will not suffice. S&P and Fitch downgraded the United Kingdom after the 2016 Brexit vote, and Moody's did the same in September 2017. While S&P recently reaffirmed its AA rating, it cautioned that the risk of a disorderly Brexit may lead to a further downgrade (Reuters, Financial Times).