No-holds-barred quiz

I deliberately left out the coast guard since London and Glasgow were involved.

Were those towns/cities the first to provide the services via 999?

Does it have something to do with call centres?

Those places are where the six BT 999 call centers are located.

Another weird thing is that I had to consult a few sites before finding one that deigned to list the call centers. Also, one mentioned 7 centers instead of 6, and another said that the exact location of one of the centers (maybe the Dundee one?) was kept secret, which I found surprising. And it's probably not that secret a secret at least locally.

It was a fun one, although there must be quite a few valid solutions to the puzzle as you initially stated it.

I found this, which says it's Glasgow. Was it the one you came across?

Of course, I immediately set out to find out where it was located. I found an article from about a decade earlier that said it was the Alexander Bain House, in Clydeside, which is a BT centre for all sorts of things. I don't think Clydeside would be considered in the centre of Glasgow. Maybe the 999 contingent was moved to its own central Glasgow location at some point, and a decision was made not to reveal this, but it seems odd to me as well. There is no obvious reason to make it a secret, and it would be odd for a company to pay for a relatively small office in an expensive central location when it had its own massive hub nearby.

Incidentally, the Coastguard (which I should have written correctly earlier) also handles incidents on rivers, and mountain rescue as as well, just to give them a bit of variety.

Clydeside could be anywhere from Clydebank right down to Greenock, although I think the latter is termed as part of Inverclyde these days. An old Luftwaffe map would give more detail.