Coltsfoot

Found this flowering on the bank of a ditch beside the cycle-path (next to the railway).

Is it a wild flower or something blown over from a local garden?

Daisy, Aster or Fleabane? Does anyone know? (see below)

Flower about 1.5cm across and 5cm high. Forgot to examine the leaves. I should go back.

Big thanks to TonyG for telling me that it is Coltsfoot (Tussilago farfara).