As my hon. Friend will be aware, major investment decisions are made when programmes are sufficiently mature in terms of design and cost estimates. For the successor submarine we expect this point, the Main Gate decision point, to be in 2016. Making investment decisions and placing contracts when projects are not sufficiently mature is likely to lead to cost growth and time delays. However, it is not possible, for any individual project, to estimate with any degree of accuracy what those costs and delays might be, precisely because the programme is not yet sufficiently mature.