Just a few years ago the Ministerial directives to the RN included putting every possible ship to sea and 'sweating' current platforms. To support this, there have been structural changes regarding personnel and increasing personnel numbers by 3000 over three years.
Then the Prime Minister commits to 'twenty four' frigates (and destroyers) by the end of the decade. Just by building new ships this could not be achieved until 2035 or thereabouts, suggesting that some current ships will need to run on longer than planned.
NATO commitments are increasing, the Middle East is not calming down....