Robertson joined the BBC in 1972. and since April 1983 he was the Corporation's official rugby union correspondent, covering the sport not only on radio but also on television. He regards Scotland's 1984 and 1990 Grand Slams and Jonny Wilkinson's winning drop-kick in the final of the 2003 World Cup as his "best on-air moments". Robertson was also a presenter of the English Premiership video review of 1998-99. In February 2018 he announced that he will be retiring at the end of the year and covered his last game, England v Australia, on 24 November 2018.