On 9 August 2019 there was a significant power cut due to lack of inertia. This duration was significantly reduced because of batteries [1]. Since then, gas turbines have been repurposed to provide inertia without generation [2]. Check out the documentary series "Guy Martin's Great British Power Trip" [3] for more national grid facts.

[1] https://www.theblackoutreport.co.uk/2023/08/09/9-august-2019... [2] https://www.nationalgrideso.com/news/deeside-power-station-b... [3] https://www.channel4.com/programmes/guy-martins-great-britis...