Mr. Seán Armstrong:

We applied discount rates from a societal perspective. These were 3% and 5%. We used the 5% rate to set building regulations. We set 7% and 10% rates from a financial perspective, which we used to inform our analysis. We decided that the 5% discount rate was the most appropriate for setting our performance requirements because we wanted to look at the situation from a societal perspective, which will give better future savings.