Point being, they are not the same. There is one hour difference between UK Time, GMT and UTC for half of the year, due to daylight saving time.
Greenwich is a borough in East London, there is an old museum with the line on the ground that defined the meridian. You can visit if you come across London.
GMT, namely Greenwich Meridian Time is not actually the time of the meridian of Greenwich for half of the year. When you find yourself working with GMT, you really need to think about how you got there because it's wrong. 90% of the time you meant to use UTC and the other 10% you meant Europe/London timezone.
The time at the greenwich meridian = not GMT
See the problem here? I know it sounds like a bad pun but it's a real problem that every developer in the UK struggled with. To make thing worse, Greenwich the location is right next to the financial district of London where thousands of developers make financial software that are one hour wrong.
I lived in Greenwich, I don't remember entering a new space-time continuum when getting off the DLR at Cutty Sark. You know, compasses spinning eratically, GPS going haywire, cuckoo clocks spinning out of control, because the bubble around the Greenwich Meridian transcends the mortal plane.
GMT is the timezone we have between the end of October and the end of March. Between the end of March and the end of October, it shifts an hour ahead and becomes BST, or GMT/UTC+1.
Greenwich is also South East London, not East London, as it is south of the Thames.
That's all I am saying. You don't have to resort to name calling.
Nobody but you seems to care about what time it is in Greenwich, including, it seems, other people who've lived in Greenwich. So GMT is fine.
It's the "Mean Solar Time[1]" at the Royal Observatory in Greenwich, London, not the legal time observed there.
The legal time switches back and forth between GMT and BST, but the mean solar time doesn't.
[1] https://en.wikipedia.org/wiki/Solar_time#Mean_solar_time
I suspect you are the one who is confused: the UK is on BST in the summer, and GMT in the winter. GMT is identical to UTC to the nearest second. GMT is not defined as "the current time in Greenwich", and I suspect your confusion is because you think it's "Greenwich Meridian Time". It's actually "Greenwich Mean Time".
The maritime museum at Greenwich is pretty cool though, as is the old observatory. You can see Harrison's clocks there.