UTC is the successor of GMT, there's no difference other than the name.
So "Railway Time" was invented in 1840 ... unified across the country, and it created a Time Zone.
Was Britain the first place this happened? I suspect it was.
Whoever came up with the sundial first would have the claim to having invented time - and the sun's not out often enough in Blighty for them to be a contender :P
Just like in New York where it's 1157 Local, or 1157 EDT (Eastern Daylight Time) - 1057 EST (Eastern Standard Time)