Michael Whitehouse, chief operating officer of the National Audit Office, warns there are significant uncertainties regarding the carrier project:

"The 2010 strategic defence and security review has radically changed the carrier strike concept. It generated £3.4 billion of savings but introduced significant levels of operational, technical, cost and schedule uncertainty.

"It will take two years for the department to reach a mature understanding of the consequences of the decision. These consequences include a decade without an operational carrier and the risks after such a time associated with reconstituting the capability.

"The risks to the delivery of the new carriers are compounded by more generic problems with defence acquisition – notably the MoD's continuing difficulties in balancing its budget."