[phaemon]

They weren't wrong at all; they were right.

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.