Britain suffered further blows to its economic standing on Monday as two top ratings agencies downgraded its sovereign credit score, judging last week's vote to leave the European Union will hurt its economy.

Standard & Poor's stripped Britain of its last remaining top-notch credit rating, dropping it by two grades from "AAA" to "AA" and warning more downgrades could follow.

Fitch Ratings also downgraded its ranking for Britain's creditworthiness by one notch, and similarly said more cuts could follow.