most expensive single fare on a bus between the shortest points and opposite

[londonbridge]

Okay, £2.30 for one stop on a London bus is pretty expensive then! (It's also pretty expensive for most journeys, which is why I am not surprised I barely ever see people pay cash)

So the answer to the question (in terms of London buses) is find the shortest distance between two stops served by the same route. Fiveways to Stafford Gardens (routes 154 and 157) may be a good contender.