Moody's downgraded the outlook on Britain's debt to negative from stable on Friday, saying Brexit had been a catalyst for an erosion in the country's institutional strength. "It would be optimistic to assume that the previously cohesive, predictable approach to legislation and policymaking in the UK will return once Brexit is no longer a contentious issue, however that is achieved," the ratings agency said.

Moody's affirmed its Aa2 rating on Britain's sovereign debt.