Mary Portas conducts a new survey into Britain's spending habits, setting out to determine whether the national events of the past year have altered the way people in the UK part with their cash. Estimates suggest the UK spends £7.5billion a week, and Mary catches up with representatives from Marks & Spencer, John Lewis, Superdrug, Poundland, Hobbycraft and Lakeland to find out how these retailers have fared. Mary also looks back at some of the retail stories of the year, such as the return of big knickers, the unicorn trend, and the popularity of Prosecco and the fidget spinner.