I was just grumbling on Facebook because I couldn’t access this via the BBC archive … it does reside on Youtube, as it turns out. From a 1966 edition of BBC Chronicle (the volume seems rather low on this):
100 days’ march… as Pliny says (NH 10.27 … via Lacus Curtius): mirum in hac alite a Morinis usque Romam pedibus venire.( fessi proferentur ad primos; ita ceteri stipatione naturali propellunt eos. ) Mirum indeed!