  We report the detection of Lyman-continuum (LyC) photons from a massive
interacting system at $z=1.097$ in the Hubble Ultra Deep Field. The LyC
detection is made in the far-ultraviolet F154W band of the UVIT telescope
onboard AstroSat. Both JWST and HST imaging of the system reveal signs that it
is a likely merger. In particular, high-resolution imaging in the JWST bands
reveals an infrared luminous object within the system that is faint in the
bluer HST bands. The ionized-gas kinematics from the MUSE-UDF data supports the
merger hypothesis. We estimate that the entire system is leaking more than $8
\%$ of its ionizing photons to the intergalactic medium. The SED-derived
stellar masses of the two components indicate that this is a major merger with
a mass ratio of ${1.13 \pm 0.37}$. This detection hints at the potential
contribution of massive interacting systems at higher redshifts, when major
mergers were more frequent, to the ionizing budget of the universe.
