  We present the first intensive continuum reverberation mapping study of the
high accretion rate Seyfert galaxy Mrk 110. The source was monitored almost
daily for more than 200 days with the Swift X-ray and UV/optical telescopes,
supported by ground-based observations from Las Cumbres Observatory, the
Liverpool Telescope, and the Zowada Observatory, thus extending the wavelength
coverage to 9100 \r{A}. Mrk 110 was found to be significantly variable at all
wavebands. Analysis of the intraband lags reveals two different behaviours,
depending on the timescale. On timescales shorter than 10 days the lags,
relative to the shortest UV waveband ($\sim1928$ \r{A}), increase with
increasing wavelength up to a maximum of $\sim2$days lag for the longest
waveband ($\sim9100$ \r{A}), consistent with the expectation from disc
reverberation. On longer timescales, however, the g-band lags the Swift BAT
hard X-rays by $\sim10$ days, with the z-band lagging the g-band by a similar
amount, which cannot be explained in terms of simple reprocessing from the
accretion disc. We interpret this result as an interplay between the emission
from the accretion disc and diffuse continuum radiation from the broad line
region.
