Over the last century, the distribution of Teloschistes flavicans has contracted from being widespread in the southern half of England and Wales to being limited to South-West England with outlying populations in Pembrokeshire and North Wales. Twelve core sites have been identified where the species is well established: ten of these are saxicolous/terricolous habitats on windy coastal cliff tops; the other two are lines of sycamore trees near the coast. At 39 further localities, some inland, the species is in very small amounts (often on one tree) and vulnerable to extinction. It is normally a member of the Parmelietum revolutae or Ramalinetum scopularis associations. The conservation of the species is discussed.