In April of this year Joni Mitchell returned to Britain for her first tour in nine years. BBCs Old Grey Whistle Test and Radio Is In Concert went to Wembley to record the last night of the tour and tonight's stereo simultaneous broadcast features highlights from that concert. Her concert included such favourites as 'Big yellow taxi', 'Free man in Paris', 'Case of you', 'Woodstock' and her hit of that year, 'Chinese cafe'.