River-class retirements and the patrol replacement gap

The proposed replacement sequence would retire the older Batch 1 River-class patrol vessels and return some Batch 2 ships from overseas duties. Type 31 frigates would take over those overseas deployments. Frigate delays disrupt this sequence while the newer patrol vessels remain committed to maritime security, diplomacy, and conflict management abroad. The older ships meanwhile face age-related retirement. A delay in frigate construction therefore puts pressure on both overseas commitments and the availability of patrol vessels at home.