Revalation! Apparently you can just tap in and out with a regular contactless debit card to travel on the Tube in London.
I should have twigged this after another trip when I’d spent 2 minutes holding up a bus vehemently denying I had a card to use with the contactless payment.
No folks, it’s not just those smug oyster lot that can get around easily now. Just make sure you tap in and out to avoid paying the highest fare.
TfL Contactless for more info.