Thousands of people at a major shopping centre have been evacuated for the second time in a week.Shoppers are reporting on social media that people are once again being asked to leave the Westfield Stratford shopping centre in London.On Sunday afternoon the evacuation alarms were once again going off with shoppers tweeting that they were leaving and asking the centre's Twitter account what was going on.Staff at the centre were ushering people towards the exits and smoke curtains were pulled...
