  Topological states enable robust transport within disorder-rich media through
integer invariants inextricably tied to the transmission of light, sound, or
electrons. However, the challenge remains to exploit topological protection in
a length-scalable platform such as optical fibre. We demonstrate, through both
modelling and experiment, optical fibre that hosts topological supermodes
across multiple light-guiding cores. We directly measure the photonic
winding-number invariant characterising the bulk and observe topological
guidance of visible light over metre length scales. Furthermore, the mechanical
flexibility of fibre allows us to reversibly reconfigure the topological state.
As the fibre is bent, we find that the edge states first lose their
localization and then become relocalised due to disorder. We envision fibre as
a scalable platform to explore and exploit topological effects in photonic
networks.
