This week Ofgem made a statement about how the UK could potentially run out of gas. Creating a shortage, and that in a emergency there could be a rolling power cut if the UK due to lack gas supplies had to turn off gas turbines that produce electricity, if we get a cold and server winter. The last time this happened was in the 1973 when the Gas supplies switched off for hours due to gas rationing and Electricity rationing was done as well.
How did we get here, Russia stopped the gas flowing to Europe and so Europe has been buying up all the Norwegian gas. Meaning less supply. Additionally France's Nuclear power stations are offline due to maintance, so there is less electricity in Europe so France has been buying (and burning) gas to meet its consumption, meaning less supply.
The UK has Approximately 7 days of Gas Stored up, but The government has been urged to set a target to slash household energy demand by 20% through Covid-style measures increasing how much gas the UK has stored to 8 days to avert potential gas shortages in winter.