The dataset contains forecasts of our Dynamic Containment Low and High requirements for the next 4-days. The methodology uses forecasted demand, inertia, and response volumes as well as a view of the largest losses on the system to estimate the DC requirements. The actual requirements day-ahead are likely to change based on optimisation carried out closer to real-time coupled with greater visibility of inertia, demand, and loss sizes. For example, changes to interconnector flows from our forecasted position can lead to either an increase or decrease in our requirements if the change impacts the largest loss we need to secure.