DailyMail: Not Russians but ‘Very old’ Transformer failed and started Heathrow Substation fire as 220,000 are stranded

Still the anti-terror squads are checking if not Russia caused the fire in an electrical sub-station that caused Heathrow Airport to close. But the DailyMail is the first to report that it was not Russia but a very old transformer that failed and caused a fire.
The question may be allowed why the World’s largest airport is connected to only one electrical substation and has not plan B in case it fails?

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