  We have carried out a radio-wavelength imaging survey of 45 bright-rimmed
clouds (BRCs), using the Australia Telescope Compact Array to characterise the
physical properties in their ionised boundary layers. We detected radio
emission from a total of 25 clouds and using a combination of Digitised Sky
Survey and mid-infrared MSX micron images classified the emission into that
associated with the ionised cloud rims, that associated with embedded possible
massive YSOs and that unlikely to be associated with the clouds at all. A total
of 18 clouds display radio emission clearly associated with the cloud rim and
we determine the ionising photon flux illuminating these clouds and the
electron density and pressure of their ionised boundary layers. Using a global
estimate for the interior molecular pressure of these clouds we show that the
majority are likely to be in pressure equilibrium and hence are currently being
shocked by photoionisation-induced shocks. We identify those clouds where the
predicted ionising photon flux is inconsistent with that derived from the
observations and show that either the spectral types of the stars illuminating
the BRCs are earlier than previously thought or that there must be additional
ionising sources within the HII regions. Finally, we identify the radio sources
embedded within the clouds with infrared stellar clusters and show that they
contain late O and early B-type stars, demonstrating that a number of BRCs are
intimately involved with high to intermediate-mass star formation.
