Officially, the fastest 250 is John McGuinness who lapped at 118.26mph on the Vimto Honda in 1999 although Bruce Anstey did get close in 2002 with 118.03mph (DTR Yamaha). I'm not sure if Shaun Harris has gone quicker, I know he did over 118mph in practice but I thought he did 117.85mph in the race (it was the 1998 Senior when he came eighth), which at the time was the fastest 250cc lap, bettering Ian Lougher's 1990 time of 117.80mph.