Part of the hull of Queen Elizabeth has arrived at Rosyth where it is to enter the dry dock for the rest of the ship’s construction. The ship, which left BAE Systems’ Portsmouth yard, is due to be finished in 2017 and will be followed by sister ship Prince of Wales.

The Ministry of Defence says the ships and jets will cost £7bn, leading some newspaper columnists to argue that they are both an unnecessary expense and no longer strategically necessary for the UK. …

Different nations take different approaches to carriers. The US owns 11, or 20 if plane-carrying amphibious assault ships are counted.