For years the London operation for Bernard Madoff's firm was a little-known outpost of his New York trading group. Now, authorities said it played a role in how Mr. Madoff carried out his alleged fraud. The development, disclosed in the government's criminal charges against Mr. Madoff on Tuesday, draws a more-direct connection between the alleged fraud and the trading operation in London, where directors and shareholders included family members and associates of Mr. Madoff.Mr. Madoff, the government alleges, used the London operation to launder client money. He carried out the alleged fraud by transferring client money from the investment-advisory business...