[patneedham]

I think the more interesting question would be which public transportation routes greater than X miles (or kilometers) in length have the highest distance to price ratio.

[jxub]

London: probably 25 miles for £1.50 (https://www.timeout.com/london/blog/how-far-can-you-go-with-...) or one of the rare £1 EasyBus tickets from Paddington to Luton which would cover around 37 miles.

The second one is not really public transportation though, and we're getting dangerously close to the £15 Ryanair flights territory.

[Symbiote]

A London Underground fare, off-peak, avoiding Zone 1, is also £1.50.

So, Heathrow Terminal 5 to Epping should be a contender. It's around 28 miles.

(And being run by a private company can't exclude MegaBus, since almost all public transport in the UK is run by private companies.)

[kimburgess]

Potential competitor: North (Gympie) to South (Varsity Lakes) on Brisbane Australia’s ‘inner city’ train network. 260km (160 miles) for AU$20 (£10.50) - cheaper off peak or with concession. Buses also extend this further in each direction using the same ticket.

[twic]

In the UK, people over 60* get a pass which lets them use buses for free. Some of them have used this to travel considerable distances:

http://news.bbc.co.uk/1/hi/magazine/7324086.stm

https://www.telegraph.co.uk/news/uknews/road-and-rail-transp...

* Correction, not 60, "female state pension age", which is currently 67; thanks for the correction, tonyedgecombe: https://www.gov.uk/apply-for-elderly-person-bus-pass

[tonyedgecombe]

67 in Oxfordshire.