Raising fares – whether it’s to pay for increased investment in infrastructure and expansion of the network, or just to pay down the deficit – must take into account the level at which commuters will no longer pay for transport by rail.

This has been acknowledged today, as Justine Greening suggests a lower fare rise of 6% for next years’ tickets.

If prices increase by too much, the loss of revenue from passengers choosing to travel by different methods of transport may even override the amount of extra funding higher fares produce.

Finding this point – the most that can be charged without dissuading a large proportion of travellers – is difficult, and affected by additional external factors, such as the amount people have to spend on other things.

Is an 8% increase too high? Of course all passengers will declare that it is, but how many of them would actually use alternative transport if fares rise this high?

Image c. Ty Stephens