LRC policy is democratically decided by our annual conference. All LRC affiliates are entitled to move a resolution at conference, which is then voted on by the whole conference. The National Executive Committee http://l-r-c.org.uk/news/story/officers-elected-at-2016-lrc-conference/ is elected each year by annual conference, and this is responsible for the day-to-day running of the LRC between conferences.
You may also be interested in the LRC Constitution.