This is a communion hymn with music by Steven R. Janco. The text is a translation done in the 1800s by John M. Neale of a seventh century latin hymn. It is a non syncopated singable (mostly – one short Eb only) song that will annoy some people for having 5 flats. Guitarists will play it capo 1 and be grinning at the discomfort of the keyboard player.
If you want a song for the assembly this ticks all the boxes.
The text is in the sample at WLP where you can purchase the sheet music and also on page ten of this parish worship aid.