The point at which fast-medium becomes fast has never been clear. Before everyone was on the speedgun, it seemed an arbitrary bit of knowledge, bestowed quite often by the descriptions in the Playfair Cricket Annual, where RGD Willis would be 'right arm fast' and IT Botham 'RFM' , a verdict that would usually extend onto the TV captioning and outwards into the great pool of common knowledge.
But now everyone is on the gun. In an excellent Guardian piece this week, Duncan Fletcher illuminated the difference between facing bowling of 130kph and 140kph. 'In Zimbabwe,' he writes, 'we actually recruited two South African baseball pitchers to come and throw at us as hard as they could from 19 yards. At first we could hardly get a bat on the ball...'
So in deference to technology, to avoid argument and to stop kicking ballsy Dirty Dirk in the teeth, we should probably pick a figure, maybe around 138-140kph, and award the unambiguous title 'fast' to anyone who can sustain that average over a few overs.