NEW YORK: William Bratton, the highly visible New York police chief, resigned Tuesday amid speculation that the city wasn't big enough for him and Mayor Rudolph Giuliani. The police commissioner gained national prominence for cutting crime rates in the city and applying corporate managment techniques to the New York City police department. "I am leaving an organization I have come to love dearly," Bratton said at a City Hall news conference. Giuliani dismissed allegations that Bratton's departure was related to an ego problem between the two men. Instead, Guiliani called Bratton's tenure "exceptional" and a "turning point in the department." The mayor even praised Bratton for making the cover of TIME magazine and earning the city good publicity. "These are two men who both want to run the city," reports TIME's Elaine Rivera. "This is the result of two egos clashing. Bratton used his position as a stepping stone for something bigger. He has always said that he'll move on to bigger and better things." Rivera also points out that Bratton is leaving when some of his actions are under scrutiny. "There are concerns over trips to the Caribbean allegedly paid for by (corporate takeover king) Henry Kravis," adds Rivera. "He's leaving just as the heat turns up." Bratton will take a New York position at First Security Services Corp. of Boston.