At least that is clear enough - previously the reason given has been the difficulty in finding the money to pay for necessary investment. Nevertheless it is time to challenge the restrictive application of Treasury rules whereby borrowing on the open market by the nationalised industries is disallowed.
Other countries do not necessarily take the same narrow view. New Zealand taxpayers, and the users of air traffic services in that region, have benefited considerably from the fact that their government is not similarly inhibited about the concept of market borrowing by publicly owned corporations.
Perhaps this country should consider the same refreshing approach. The privatisation of a key national asset is not the only available alternative when a government is reluctant to provide essential finance.