Damocles said:Oh, Gordon Brown apologised officially, so it's all water under the bridge now.
Lloyd George was born in Manchester but bred in Wales, are we counting him or just born and bred Mancs?
Born and bred Mancs, I'll pick J. J. Thomson. He found the electron and isotopes, invented the mass spectrometer and won the Nobel Prize. Not bad for kid from the factories in Cheetham Hill. He had a kid who won the Nobel as well if I recall.
Again, probably not the most popular choice, but another guy who will be remembered long after most popular choices are dead. The electron is quite important to every piece of science to be honest.
Originally I was just thinking born and bred Mancs, but maybe the boundaries should be changed to open it up a bit. Maybe having resided in Manchester for a significant period should suffice, which would include the likes of Turing, Halle, and Rylands (as johnmc mentioned). I guess Engels would be pushing it a little.
JJ Thomson is a good shout.