Heinz Ketchup and McCain have linked up in a cross-couponing campaign to boost impulse purchases of both brands. In March and April 800,000 bottles of 570g Heinz Tomato Ketchup will carry neck collars offering consumers 50p off their next purchase of 907g and 1.81kg packs of McCain Oven Chips. Those same packs of McCain Oven Chips will offer 30p and 50p (respectively) off consumers' next purchase of a 570g or larger bottle of Heinz Tomato Ketchup. Sue Jefferson, McCain senior marketing manager, said: "Both brands are set to gain because of the extra awareness and extra impulse purchases it will prompt." Heinz has also announced that it is developing the Heinz Tomato Ketchip ­ a chip that already contains a squirt of ketchup. According to a NOP survey, 55% of adults eat tomato ketchup with chips. {{P&P }}