In Tapper v Eyre 43 TC 720 it was held that a mini van used solely for business purposes was nevertheless a vehicle commonly used as a private vehicle. A similar judgement was given in Laing v IRC 44 TC 7682. However, in Roberts v Granad TV Rental 46 TC 295 a different view was taken. In this case it was held that even if a majority of vehicles were registered for private use, this did not mean that they were necessarily suitable for such use. Similarly, in S&U Stores v Gordon 1970 WLR 889 the test was one of suitability and not usability.
A family car fitted with dual controls (which could have been removed within two hours) were of a type not commonly used on a private vehicle and unsuitable to be so used. Bourne v Auto School of motoring (Norwich) 42 TC 217
A salon car fitted with a flashing light for use by a fireman was not commonly used as a private vehicle and was unsuitable for such use. The court relied on the fact that it would be illegal for anyone other than the emergency services to drive a vehicle adapted in this way. Gurney v Richards 1989 STC 682