London Buses - Route 399 from Barnet to Hadley Wood 

Probably one of the rarest, and least used, services in North London. Route 399 started in 1993 as a service from Hadley Wood to Barnet General Hospital (operated by Welwyn Hatfield Line), but was diverted the following year to Western Way. In 1996, the Barnet-Western Way section was split off as service 389 and the 399 has remained unchanged since then. It was also operated by Thamesway and First Capital, before passing to London General in 2012. It runs 5 times a day, off peak, Mondays to Saturdays.
Route 399 serves one of the most prosperous areas of suburban London; the clientèle appear to be a handful of elderly people (who probably live with their stockbroker children) and cleaners. It's frankly astonishing that public money continues to sustain a service like this. But it's a pretty route.....