  The Gaia Collaboration has recently reported the detection of a 33 M$_\odot$
black hole in a wide binary system located in the Solar neighbourhood. Here we
explore the relationship between this black hole, known as Gaia BH3, and the
nearby ED-2 halo stellar stream. We study the orbital characteristics of the
Gaia BH3 binary and present measurements of the chemical abundances of ED-2
member stars derived from high-resolution spectra obtained with the VLT. We
find that the Galactic orbit of the Gaia BH3 system and its metallicity are
entirely consistent with being part of the ED-2 stream. The characteristics of
the stream, particularly its negligible spread in metallicity and in other
chemical elements as well as its single stellar population, suggest that it
originated from a disrupted star cluster of low mass. Its age is comparable to
that of the globular cluster M92 that has been estimated to be as old as the
Universe. This is the first black hole unambiguously associated with a
disrupted star cluster. We infer a plausible mass range for the cluster to be
relatively narrow, between $2\times 10^3M_\odot$ and $4.2\times 10^4M_\odot$.
This implies that the black hole could have formed directly from the collapse
of a massive very-metal-poor star, but that the alternative scenario of binary
interactions inside the cluster environment also deserves to be explored.
