Scottish Power said around 50,000 homes and businesses in the south of Glasgow were left in the dark on Tuesday evening as a fire broke out in an underpass below one of the busiest motorways in Scotland.
Electrical piping with cables carrying 132,000 volts of electricity were caught up in the blaze underneath the M8 near Renfrew, which caused the motorway to close down for four hours between junction 25 and 27.
Fire and Rescue services tackled the fire along with gas and electricity engineers, who were able to re-establish power to all the homes within 30 minutes.
Strathclyde police said they are treating the fire as deliberate.
Detective Sergeant Gordon McCrae, of Paisley CID, who is leading the investigation, said: "From our enquiries so far, it would appear that the electrical cables in the disused underpass were set alight, which resulted in damage and disruption."
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