Tesco CEO Dave Lewis has admitted he is concerned by the aggressive marketing investment of discounters Aldi and Lidl. Speaking to Marketing he said the accelerated pace of the discounters' investment concerned him. "It concerns me at one level," he said, "but where we are at the moment is taking a step back and [looking at] what is driving the brand experience - it’s in store. I’m not interested in share of voice type conversations. I’m interested in what the [customer] experience is first and foremost."