from http://adactio.com/journal/display.php/20041215003521.xml I did a little research and found out that the typeface was actually commissioned by Frank Pick way back in 1916. It's the work of one Edward Johnston in whose name a foundation has been formed. The typeface was slightly tweaked in 1980 but it has been more or less in constant use for almost 90 years.
The collaboration of Pick and Johnston must have been a match made in heaven. They also gave us the superb London Underground roundel.
Students of Johnston founded, in 1921, the SSI - Society of Scribes & Illuminators, probably the world's foremost calligraphy society.