The HCC.4 was given a VVIP interior, had a special maintenance routine (inspected more often, parts replaced earlier etc.) and entered service with the Queen's Flight at RAF Benson in June 1969, replacing two Whirlwind
HCC.12s. Their first major duty was the investiture of the Prince of Wales at Caernarfon Castle in July 1969. Following a reorganisation of royal flying, they were later transferred to 32 (The Royal) Squadron at RAF Northolt. 2 built, they were both painted overall red with a royal blue upper fuselage.