Wall Street and the FTSE 100 both fell sharply in a wild day of trading after the UK voted for Brexit.
The London blue-chip index fell 7% in early trading to just over 5,800 points but ended the day 3.15% lower at 6,138.
New York and European markets all suffered even bigger falls, with the Dow Jones posting its biggest one-day slide in almost five years.
Sterling also plunged, falling more than 8% against the dollar and 6% against the euro.
Credit rating agency Moody's cut the UK's outlook from stable to negative on Friday night, saying the Brexit vote could result in weaker economic growth.
Wall Street fell sharply in late trading, with the Dow plunging more than 600 points, or 3.4%, to close at 17,400 points.