The Cuckoo Line is an informal name for the now defunct railway service which linked Polegate and Eridge in East Sussex, England, from 1880 to 1968. It was nicknamed the Cuckoo Line by drivers, from a tradition observed at the annual fair at Heathfield, a station on the route. At the fair, which was held each April, a lady would release a cuckoo from a basket, it being supposedly the 'first cuckoo of spring'. The railway line served the following Sussex communities: Polegate, Hailsham, Hellingly, Horam for Waldron, Heathfield, Mayfield, Rotherfield and Eridge. Services continued through Eridge and onward via Groombridge to Tunbridge Wells.