We report here the reliable and efficient operation of a mini-TEA CO₂ laser utilizing uniform field electrodes wherein the parallel spark channels of the preioniser, an integral part of the laser, functioned as a switch as well as a source of UV photons. The operation of the laser has been realized up to a maximum energy loading of ~197 J/l atm under widely varying gas composition including helium lean as well as helium-free gas mixtures. Under most optimized conditions the laser operated with an efficiency of ~7.1%. The spatially symmetric nature of the emission from the laser in spite of the one sided preionisation points to the effectiveness of the excitation circuit employed here to energise the laser.