Sir Martin Sorrell has said that the bullish “Don Draper-ish” attitude of the ad industry is misplaced, warning of concerns such as a possible Brexit from Europe. The WPP chief executive’s comments came as his marketing services group reported a 2.8% boost to pre-tax profits to GBP1.49bn, having finished the year with a strong fourth quarter and started 2016 above target. But Sorrell remained typically bearish on advertisers that are too focused on cost cutting over investing for growth.