  We report the serendipitous discovery of an extremely intermittent radio
pulsar, PSR J1710-3452, with a relatively long spin period of 10.4 s. The
object was discovered through the detection of 97 bright radio pulses in only
one out of 66 epochs of observations spanning almost three years. The bright
pulses have allowed the source to be localised to a precision of 0.5" through
radio imaging. We observed the source location with the Swift X-ray telescope
but did not detect any significant X-ray emission. We did not identify any
high-energy bursts or multi-frequency counterparts for this object. The
solitary epoch of detection hinders the calculation of the surface magnetic
field strength, but the long period and the microstructure in the single-pulses
resembles the emission of radio-loud magnetars. If this is indeed a magnetar,
it is located at a relatively high Galactic latitude (2.9 degree), making it
potentially one of the oldest and the most intermittent magnetars known in the
Galaxy. The very short activity window of this object is unique and may point
towards a yet undetected population of long period, highly transient radio
emitting neutron stars.
