  We report here on the discovery of a red quasar, J004929.4+351025.7 at a
redshift of z = 2.48, situated within a large Lya emission-line halo. The radio
spectral energy distribution implies that the radio jets were triggered < 10^4
years prior to the time at which the object is observed, suggesting that the
jet triggering of the active galactic nucleus is recent. The loosely biconical
structure of the emission-line halo suggests that it is ionised by photons
emitted by the central quasar nucleus and that the central nucleus is obscured
by a dusty torus with Av ~ 3.0. The large spatial extent of the Lya halo
relative to the radio emission means this could only have occurred if the radio
jets emerged from an already established highly-accreting black hole. This
suggests that the radio-jet triggering is delayed with respect to the onset of
accretion activity on to the central supermassive black hole.
