"Moody's Investors Service ("Moody's") has today changed the outlook on the Government of the United Kingdom's Aa2 ratings to negative from stable ... The change in outlook to negative from stable is driven by two factors: 1. UK institutions have weakened as they have struggled to cope with the magnitude of policy challenges that they currently face, including those that relate to fiscal policy. 2. The UK's economic and fiscal strength are likely to be weaker going forward and more susceptible to shocks than previously assumed," the agency wrote in a statement on Friday, adding that "Brexit has been the catalyst for this erosion in institutional strength."

"The outlook on the Bank of England's Aa2 issuer and senior unsecured bond ratings and the (P)Aa2 on its senior unsecured MTN programme has also changed to negative from stable; the Aa2 and (P)Aa2 ratings have been affirmed. The short-term issuer ratings have been affirmed at Prime-1," the agency added.