Through the line marketing is a single campaign that unites above the line and below the line to reflect how people really consume media. In the UK, viewing time is spread across broadcast, on demand and video sharing platforms, so a cross channel plan is now essential for reach, recall and profit. The strongest evidence shows most advertising payback arrives over the long term and that TV and BVOD are powerful scale engines when paired with targeted channels like search, social and retail media. TTL brings those pieces together under one creative platform and one measurement framework.