[Closed] Graphic Designers: What's the legality of using the Johnston typeface?

I mean, I legally 'own' a copy of the font, but in the context of using it for a website aimed at Londoners, any ideas on the legality? Will I get sued by London Transport? Can't find any info regarding this on Google.

Is it part of a 'brand identity' and therefore subject to copyright in the same sense as a logo or picture? Or can I just use it freely?