Escort cruisers created a need for large destroyer leaders

British cruiser work developed along missile-cruiser and helicopter-cruiser strands that intersected with the CVA-01 future-fleet programme. The helicopter branch eventually led toward the Invincible class, although surviving accessible documents do not yet settle whether 'through-deck cruiser' was an official contemporary term. An aviation cruiser could not safely lead a gun or missile surface action group into close combat, just as earlier support carriers were not intended to join the battle line. Surface groups nevertheless remained in doctrine, illustrated by Falklands escorts manoeuvring to prevent the General Belgrano group from reaching gun range of the carriers. The gunless first batches of Type 22 frigates show how strongly missile-era thinking could pull in the other direction even though surface-action doctrine had not disappeared. A separate large destroyer was therefore needed as principal carrier escort, anti-submarine hunting-group leader, convoy commander, and commerce-protection ship. Missile developments including Sea Dart, Sea Wolf, Ikara, and anti-ship weapons increased the space and coordination burden placed on that leader. The resulting concept resembles the modern Japanese Hyuga class in combining group leadership and aviation support without treating the ship as a conventional gun cruiser.