Married, middle-aged, Graeme Stening (51) [allegedly] had sex in the street with a prominent barrister ... outside one of the Capital's busiest rail stations during the peak rush hour!

Seems passers-by had more than a "peek" - and it wasn't only the eminent QC who happened to be 'prominent' - when, after a few "stiff" drinks, something else reached its "peak" ... leading the randy pair to (albeit NOT "on the QT") together.

Clearly, he had "met his Waterloo"!