The robotic 2m Liverpool Telescope, based on La Palma, is owned and
operated by Liverpool John Moores University. It has a diverse
instrument suite and a strong track record in time domain science,
with highlights including early time photometry and spectra of
supernovae, measurements of the polarization of gamma-ray burst
afterglows, and high cadence light curves of transiting extrasolar
planets. In the next decade the time domain will become an
increasingly prominent part of the astronomical agenda with the
arrival of new facilities such as LSST, SKA, CTA, Gaia and the next
generation of exoplanet finders. Additionally, detections of
astrophysical gravitational wave and neutrino sources opening new
windows on the transient universe. To capitalise on this exciting new
era we intend to build Liverpool Telescope 2: a new robotic facility
on La Palma dedicated to time domain science. The next generation of
survey facilities will discover large numbers of variable and
transient objects, but there will be a pressing need for follow-up
observations for scientific exploitation, in particular spectroscopic
follow-up. Liverpool Telescope 2 will have a 4 metre aperture,
enabling optical/infrared spectroscopy of faint objects. Robotic
telescopes are capable of rapid reaction to unpredictable phenomena,
and for fast-fading transients like gamma-ray burst afterglows, this
rapid reaction enables observations which would be impossible on less
agile telescopes of much larger aperture. We intend Liverpool
Telescope 2 to have a world-leading response time, with the aim that
we will be taking data with a few tens of seconds of receipt of a
trigger from a ground- or space-based transient detection facility. In
this talk I will discuss the role for Liverpool Telescope 2 in the
2020+ astronomical landscape, the key science topics we hope to
address, and the results of our preliminary optical design studies.