Timekeepers gathered in Geneva on Thursday to thrash out a contested proposal to abolish a 40-year-old practice of adding the occasional second to world time. Members of the International Telecommunication Union (ITU) are pondering the future of the \"leap second.\" It is the extra moment that is added to atomic clocks to keep them in sync with Earth\'s rotation, which is slowed a tiny bit by the gravitational pull of the Sun and the Moon. Without the leap second, hi-tech clocks would race ahead of solar time, amounting to a disprepancy of about 15 seconds every 100 years, experts believe. The second has been added on 24 occasions since the ITU defined Coordinated Universal Time (UTC) 40 years ago. But critics say the practice should be scrapped. Every time a second is added, the world\'s computers need to be manually adjusted, a costly practice that also boosts the risk of error. \"A decision is most likely, either by consensus or perhaps by a vote,\" said an ITU spokesman ahead of the session at the Radiocommunication Assembly later Thursday. If the vote is passed, it would need to be ratified by the ITU\'s World Radiocommunication Conference beginning next week. The United States and France are among those countries which supported the move in a survey carried out by the body last year, while Britain, Canada and China were against.