  We report new observations of "Hanny's Voorwerp" (hereafter HV) taken from
the second data release of the LOFAR Two-metre Sky Survey (LoTSS). HV is a
highly-ionised region in the environs of the galaxy IC2497, first discovered by
the Galaxy Zoo project. The new 150MHz observations are considered in the
context of existing multi-frequency radio data and archival narrow-band imaging
from the Hubble Space Telescope, centred on the [Oiii] emission line. The
combined sensitivity and spatial resolution of the LoTSS data -- which far
exceed what was previously available at radio frequencies -- reveal clear
evidence for large-scale extended emission emanating from the nucleus of
IC2497. The radio jet appears to have punched a hole in the neutral gas halo,
in a region co-located with HV. The new 150MHz data, alongside newly-processed
archival 1.64GHz eVLA data, reveal that the extended emission has a steep
spectrum, implying an age $>10^8$yr. The jet supplying the extended 150MHz
structure must have "turned off" long before the change in X-ray luminosity
reported in recent works. In this picture, a combination of jet activity and
the influence of the radiatively efficient active galactic nucleus are
responsible for the unusual appearance of HV.
