  The formation and dynamical history of hot Jupiters is currently debated,
with wide stellar binaries having been suggested as a potential formation
pathway. Additionally, contaminating light from both binary companions and
unassociated stars can significantly bias the results of planet
characterisation studies, but can be corrected for if the properties of the
contaminating star are known. We search for binary companions to known
transiting exoplanet host stars, in order to determine the multiplicity
properties of hot Jupiter host stars. We also characterise unassociated stars
along the line of sight, allowing photometric and spectroscopic observations of
the planetary system to be corrected for contaminating light. We analyse lucky
imaging observations of 97 Southern hemisphere exoplanet host stars, using the
Two Colour Instrument on the Danish 1.54m telescope. For each detected
companion star, we determine flux ratios relative to the planet host star in
two passbands, and measure the relative position of the companion. The
probability of each companion being physically associated was determined using
our two-colour photometry. A catalogue of close companion stars is presented,
including flux ratios, position measurements, and estimated companion star
temperature. For companions that are potential binary companions, we review
archival and catalogue data for further evidence. For WASP-77AB and WASP-85AB,
we combine our data with historical measurements to determine the binary
orbits, showing them to be moderately eccentric and inclined to the line of
sight and planetary orbital axis. Combining our survey with the similar Friends
of Hot Jupiters survey, we conclude that known hot Jupiter host stars show a
deficit of high mass stellar companions compared to the field star population;
however, this may be a result of the biases in detection and target selection
by ground-based surveys.
