She joined the BBC in 1985 as a producer on Radio 4's Today programme. She has been a reporter on the Today programme and BBC Breakfast News. She was also on the Spotlight programme based in Plymouth from 1989. She helped to launch Radio Five Live in 1994. Sanderson was one of the launch presenters for BBC News 24 in 1997 and could often be seen presenting the 1-4pm slot on News 24 alongside Bill Turnbull or Chris Eakin.
As of April 2008, Sanderson is one of the main presenters of World Briefing on the BBC World Service. She occasionally presents the BBC's daily audio news podcast Newspod. In April 2013 World Briefing was replaced by The Newsroom which Sanderson continues to present.