Realtime Software was the trading name of Realtime Games Software Limited and was founded in Leeds by by Ian Oliver, Andrew Onions and Graeme Baird.
They published a series of titles for the Sinclair ZX Spectrum (including 3D Tank Duel and 3D Star Strike), but unfortunately, only released two programs for the Sinclair QL:
Realtime were probably best known for releasing Carrier Command for the Amiga and Atari ST (with a ZX Spectrum conversion) in 1988 - it would have been great to see this converted to the QL.