As many famous UK retailers like Debenhams and Marks & Spencer announce store closures, multichannel retailers increasingly need to adjust their store portfolio to stay profitable. This report introduces Forrester's UK Store Scenario Planner, a tool that gives multichannel retailers insight into how they might need to change their store portfolios in the future. We used this tool to generate insight for the UK retail market as a whole. This is an update of a previously published report; Forrester reviews and updates it periodically for continued relevance and accuracy.