Ann: Managing Director Presentation, RRS Conference, page-29

I believe that's thereabouts correct.

Just did a quick google as my memory from accounting theory at uni is a bit hazy obviously...

"It's the rate of return that the investors expect or the cost of borrowing money. If shareholders expect a 12% return, that is the discount rate the company will use to calculate NPV. If the firm pays 4% interest on its debt, then it may use that figure as the discount rate."

"Net present value (NPV) is the calculation used to find today's value of a future stream of payments. ... The NPV relies on a discount rate of return that may be derived from the cost of the capital required to make the investment, and any project or investment with a negative NPV should be avoided."