Liz Phair has cancelled her summer tour with Alanis Morissette and Garbage due to “unforeseen circumstances”.The Chicago singer-songwriter, who released her new album ‘Soberish’ last month, was due to head out on tour in August to commemorate the 25th anniversary of Morissette’s landmark third album ‘Jagged Little Pill’.The US tour is set to kick off on August 12, followed by a run of UK and Ireland dates in October which Phair was supposed to be on.