  TORCH is a time-of-flight detector designed to perform particle
identification over the momentum range 2$-$10 GeV/c for a 10 m flight path. The
detector exploits prompt Cherenkov light produced by charged particles
traversing a quartz plate of 10 mm thickness. Photons are then trapped by total
internal reflection and directed onto a detector plane instrumented with
customised position-sensitive Micro-Channel Plate Photo-Multiplier Tube
(MCP-PMT) detectors. A single-photon timing resolution of 70 ps is targeted to
achieve the desired separation of pions and kaons, with an expectation of
around 30 detected photons per track. Studies of the performance of a
small-scale TORCH demonstrator with a radiator of dimensions 120 $\times$ 350
$\times$ 10 mm$^3$ have been performed in two test-beam campaigns during
November 2017 and June 2018. Single-photon time resolutions ranging from 104.3
ps to 114.8 ps and 83.8 ps to 112.7 ps have been achieved for MCP-PMTs with
granularity 4 $\times$ 64 and 8 $\times$ 64 pixels, respectively. Photon yields
are measured to be within $\sim$10% and $\sim$30% of simulation, respectively.
Finally, the outlook for future work with planned improvements is presented.
