We present high-speed , three-colour photometry of the eclipsing dwarf nova PHL 1445 , which , with an orbital period of 76.3 min , lies just below the period minimum of \sim 82 min for cataclysmic variable stars .
Averaging four eclipses reveals resolved eclipses of the white dwarf and bright spot .
We determined the system parameters by fitting a parameterised eclipse model to the averaged lightcurve .
We obtain a mass ratio of q = 0.087 \pm 0.006 and inclination i = 85.2 \pm 0.9 ^ { \circ } .
The primary and donor masses were found to be M _ { w } = 0.73 \pm 0.03 M _ { \odot } and M _ { d } = 0.064 \pm 0.005 M _ { \odot } , respectively .
Through multicolour photometry a temperature of the white dwarf of T _ { w } = 13200 \pm 700 K and a distance of 220 \pm 50 pc were determined .

The evolutionary state of PHL 1445 is uncertain .
We are able to rule out a significantly evolved donor , but not one that is slightly evolved .
Formation with a brown dwarf donor is plausible ; though the brown dwarf would need to be no older than 600 Myrs at the start of mass transfer , requiring an extremely low mass ratio ( q =0.025 ) progenitor system .
PHL 1445 joins SDSS 1433 as a sub-period minimum CV with a substellar donor .
These existence of two such systems raises an alternative possibility ; that current estimates for the intrinsic scatter and/or position of the period minimum may be in error .