LONDON, Dec 20: Britain's press watchdog committee has announced a stricter privacy code for newspapers, including a new offence of ``persistent pursuit,'' following the death of Princess Diana.The press complaints commission had foreshadowed a stricter code after Diana was killed in a car crash on August 31 in Paris in a high-speed flight from photographers.The code, which takes effect on January one, stipulates that children under the age of 16 should not be subjected to ``unnecessary intrusion,'' a clause apparently aimed partly at protecting Diana's sons, Prince William, 15, and Prince Harry, 13.Since Diana's death, British newspapers have largely observed pledges to leave the young princes alone, publishing only the occasional officially sanctioned picture, usually with their father, Prince Charles.Yesterday, Commission chairman Lord Wakeham described the code as ``the toughest in Europe.''However, it remains essentially self-regulatory. Britain, unlike France, has no privacy laws, and the only sanctions for violations of the code are that a publication must publish a critical finding.``I believe that the important changes we have made in the code show that press self-regulation can and does respond speedily to public concern,'' said Sir David English, chairman of Associated Newspapers.Sir English, whose company owns two big national tabloids, the Daily Mail and The Mail on Sunday, was among proprietors who promised to stop buying paparazzi photographs during an outpouring of national grief and press embarrassment over Diana's death.Publishers and editors of newspapers, from broadsheets to mass-circulation national tabloids, have pledged to abide by the code, which lays down rules about privacy, harassment and buying stories.However, it stops short of outlawing, for example, taking snatched pictures of people in specific public places, such as restaurants, churches or beaches - a paparazzi practice that regularly upset Diana.The code frowns on intrusions, including long-lens photography of people in private places.