Where only one big ITV region opts out

Actually that's a good point. It may have been logistically easier for Grampian to send the tape to LWT and take a feed from there - didn't regions that were doing their own thing have a feed from Thames/LWT in case of a newsflash (and later for Oracle)?

Another possibility is that the programme was networked and recorded in advance by every ITV region, but only LWT decided to show it in addition to Grampian. This may have been done because the programme was deemed a bit sensitive.

The ITV network was used to distribute programmes between different regions that would be played out locally later (along with various other pieces of video material) during times when networked programmes were not being shown.

I know that newsflashes (and all ITN bulletins) got on the air via THS/LWT. If a newsflash was screened in the middle or at the end of Coronation Street, for example, Thames would feed the newsflash to Granada who would network it to everyone (as all stations were already linked up to Granada).. but if they were doing their own thing at the time, I assume they would get a link straight to THS/LWT. Are you saying there was always a THS/LWT line open “on standby” for such occasions?

I recall a newsflash during the Falklands War in 1982 which appeared on Tyne Tees in the middle of Crossroads, which in that era they scheduled at 6.02pm and I believe were playing out themselves. At the end of the newsflash, the newsreader said “and now I hand you back to Andrew Gardner at Thames” (Thames News being in progress in the capital). Of course we didn’t join Andrew - after a long fade through black our own CA appeared and announced back into Crossroads. The feed of ITN appeared to be clean, albeit routed via Thames.

But why tie up a VT machine twice if you are showing it at the same time as the originating company and can just take a feed from them?

That's my understanding, THS/LWT would always be routed directly or indirectly so that they could get newsflashes on air immediately. So if everybody was taking Corrie from Granada, Granada could feed ITN via THS to the network. If a station wasn't taking a network programme they would get a feed from THS directly - which I think they needed for teletext too.

I understand that some of the smaller stations couldn’t feed the network directly - CTV, obviously, and I think UTV. Not sure about GPN - they certainly played out material that was also shown on STV and BOR.

I suspect, in this instance, GPN - if they were able to - pre-fed the programme to all stations who wanted to show it but schedule it themselves. Or they recorded it from either GPN or LWT that Sunday night.

Yes Grampian could certainly feed STV, no reason why they couldn't feed to other stations.

Just for completeness the original article I got this from has gone but the way back machine has it.

https://web.archive.org/web/20120302135645/http://www.transdiffusion.org/emc/insidetv/history/london.php

Well, that article is basically about LWT, and - unless I’ve missed something - nowhere does it say LWT were the only region to show the L&G programme, nor that it showed the programme at the same time as Grampian. This part of the article appears to be referring to the early-mid 70s, and there was less networking going on then than in later years - but perhaps LWT part-networked this programme, or other regions scheduled it at a different time.

It’s also worth noting that Grampian often showed L&G before the rest of the country saw it, even during schools hours. Most regions scheduled it in the Summer Term, but Grampian were known to show it in Autumn or Spring as a local opt-out or additional programme. So London schools may not have been watching the series at the same time as those in North Scotland!

Possibly because the programme was a bit sensitive so a decision was made (by Grampian?) that the programme would be reviewed by individual ITV companies and those which decided to show it would play it out themself. Has anybody got proof that both Grampian and LWT showed the programme at exactly the same time?

What about the Emmerdale shown by STV and TSW in the OP. Was that really networked to just 2 regions by YTV who weren't even showing it themself?

It’s possible YTV would have played it out for them, but it may not have been convenient for them to do so at the time TSW and STV chose to show it. It’s more likely one of the stations was pre-fed the programme by YTV during a quiet period for their VT dept (maybe a couple of episodes at a time), and this station recorded it and played it out to both stations. Or if they were showing it after YTV did, one of the stations would have taped it off the YTV feed when they showed it. Or they may even have been sent the tapes. It probably depended on what was most convenient and cost-effective. There was no “right” or “wrong” procedure.

EDIT: I now realise you are asking about this specific occasion, which may have been a “one-off”, but the answer largely still applies. I think, if it was Christmas, YTV most likely pre-fed the show to either STV or TSW a day or so in advance.