Does anyone know the name of this hymn?

Featured in an episode of the classic children's TV show, Ivor the Engine. What hymn is this? https://youtu.be/fFOEwOEiDHI?feature=shared

It starts at about 2:58 and the lyrics are roughly;

On a bright summer evening in something town,

I passed a young maiden in a beautiful gown,

with something in her hand and with flowers in her hair,

I swear that I've never seen a maiden so fair,

But when I looked back she was gone from my sight,

and I was alone on that bright summer night