When was that?I remember standing in the old North Thames gas control room in Staines one March evening waiting to see if we could make it through the evening peak. We did, just.
*I don't know what todays emergency plan looks like but back then there was a plan to shut down regional networks to protect London. Part of that rationale was the challenge of regassing the London distribution network. In addition the undergorund was powered by a gas-fired power station in Fulham although that's no longer the case.
The UK gas system has evolved quite a bit in recent years. We have 1/3 of European LNG import capacity and the North Sea now so there should not be a physical shortage of gas providing the shippers get themselves organised to contract supplies. Its a question of price but physical supply should be available.
Problem is we actually have shut down and demolished some of our CCGTs as the subsidised wind and solar undercut them. Now we don't have them in winter to convert imported gas to electricity when we really need them.
That said, I completely agree with you, it is a certainty they will cut off the regions from the gas and electric network to keep the lights on in London. National Grid know the political impact of having politicians and senior civil servants and media types sat in the dark for a few hours in London. A few years ago there was power cut in London due to a fuse failing in a part of the local distribution network. Sky News and BBC went into meltdown. There was a weeks of power outages in the North due to Storm Arwen and it barely got a mention for the first week.