New Delhi, Jan. 20 -- The third and final round in Prince Harry 's battle with the British tabloids began Monday with his lawyer alleging that the Daily Mail and its sister Sunday newspaper engaged in a "clear, systematic and sustained use of unlawful information gathering" for two decades.

Attorney David Sherborne said a longstanding culture of hiring private investigators who practiced "dark arts" to spy on celebrities for scoops had left Harry distressed and isolated.

It was "disturbing to feel that my every move, thought or feeling was being tracked and monitored just for the Mail to make money out of it," Harry said, according to his lawyer's written opening statement.

The intrusions were "terrifying" for his loved ones, created a...