The letter combination VC (for Vickers Commercial) was only used for marketing purposes and was used as follows:
VC-1 Viking
VC-2 Viscount
VC-3 Proposed civilian development of the Varsity
VC-4 A three engined airliner for the North Atlantic route
VC-5 A long range transport based on the Valiant
VC-6 A short range transport based on the Valiant
VC-7 The 1000 design
VC-8 Viscount 800 series (?)
VC-9 Vanguard
VC-10 The VC-10
VC-11 A short range version of the VC-10
VC-12 Short range transport