Demand for native ad formats and online video accelerated the growth of ad spend in the first half of the year, when it rose 5.2% to hit GBP9.9bn, according to the latest Advertising Association/Warc expenditure report. Internet ad spend was among the biggest drivers, having increased 16.9% to reach GBP4.7bn over the first half of the year. Within that, mobile grew 52.6% to GBP1.7bn.