Ms Amy Ball:

I will start with the Deputy's original statement on the cost relative to the benefits. Under our model the differences relate to discount factors and internal rates of return.

We are looking at the same baselines as the Department so we are consistent with that. Our client is very comfortable that we are using the right numbers in our published business case - our cost-benefit analysis, CBA.

On the second point about the assumed benefits, as we talk through benefits and look at them over a 25-year term, economic assumptions need to be made. Forecasts, by their nature, can be subjective. That is why this very good governance process is in place with the Department of Public Expenditure and Reform and the public spending code where there is strong and robust evaluation of any cost-benefit analysis cases. As such, I would be comfortable in saying that our assumptions are very well grounded in empirical research. They have been evaluated by very qualified people. We have referred to similar case studies across other countries and we also have adopted a very conservative approach. We have some specific instances where we can show that we pared back benefits. As the Deputy said, this is an assumption-based process so we wanted to make sure that we did not overstate benefits in any way.

The Deputy mentioned the perceived flaw in the information. I refer the Deputy to the response I gave to Deputy Dooley when I went through the process of the creation of the CBA. Where the costs were coming from another source, there was strong programme governance in place to the Department. We are in constant communication with the Department. This is a complex programme. The costs were moving as the new bidder costs were coming through. There was a difference in costs in terms of the exclusion or inclusion of certain operator costs. Other costs which were moving were the contingencies. When the error was identified, the proper checks and balances kicked in and the error was communicated to us. We promptly remedied it within our CBA.