Well, it’s taken eight months and an appeal to the Information Commissioner but TfL has now published the MJTs from every station to every other station as I requested. No doubt it will soon appear at https://tfl.gov.uk/corporate/transparency/freedom-of-information
I’ve not had time to analyse it yet but a quick glance suggests that the data was worth the effort as https://tfl.gov.uk/fares/how-to-pay-and-where-to-buy-tickets-and-oyster/pay-as-you-go/keep-within-maximum-journey-times certainly doesn’t tell the whole story. For example, a journey entirely within z1 should be 90mins but Barbican to Shoreditch HS is 100mins (all Shoreditch’s seem to be uplifted by 10mins, reflecting that it’s only in z1 for charging).
I now have a lot of work to do to convert it to a format which is useful for me, especially when out and about. I suggested to TfL that the MJT be included on the Single Fare Finder; I’ll repeat that request when I reply. However, as I’d be surprised if that happened maybe it’s something Mike could add to his fare finder. Mike, if you’d like me to mail it to you just ask. The CSV is 450,000 lines and 23Mb though it compresses to 4Mb.