A 'stretched Spartan' design was considered as a future replacement for the FV430, adapted by adding an extra road wheel enabled allowed 3 more dismounted personnel (7+3 crew), and replacing the Jaguar petrol engine with a Perkins diesel offered greater range. CVR(T) prototype number 11 (a Scorpion) was cut and extended to demonstrate the basic hull could be used as a ten-man Armoured Personnel Carrier (APC), and a diesel engine fitted. When tests confirmed the stretched version retained the mobility of the basic CVR(T) MVEE then built another prototype from scratch with a wider hull called the FV4333, later renamed Alvis Stormer (Alvis having purchased the design rights). The Alvis Stormer and subsequent developments are described in a separate article.