On May 19, 3:22*pm, wrote:

Has there ever been a time in London when a station was opened for revenue
service, even though it was clearly unready for it?

It would not surprise me to find out that this happened several times.

St Paul's Thameslink? That opened before they'd covered the cut-and-
cover tunnel in which the final station was to be...

And what about the Heathrow Express temporary station? That was open
for less than a year IIRC...