Strict colourings of STS(3v)s and uncolourable BSTS(3v)s

Strict colourings of STS(3v)s containing three mutually disjoint subsystems of order v are examined. An upper bound for χ¯ of STS(3v) linked with χ¯ of its subsystems of order v is determined and an infinite class of uncolourable BSTS(3v)s is found.