The operator of Britain’s power distribution system sought to shift blame for once-in-a-decade blackouts last week to local networks as the government laid out a more detailed investigation into the power failure.

National Grid Plc Chief Executive Officer John Pettigrew said his company’s system returned to service seven minutes after two major generation plants unexpectedly stopped working on Aug. 9. He said it was grid operators downstream of his company’s network of distribution lines that decided to shut off supplies to hospitals and rail stations, causing hours of delays long after power returned to the grid.

Pettigrew’s remarks in the Financial Times and on British Broadcasting Corp. radio on Wednesday spread the blame for the outages and underlined National Grid’s reputation for responsibly managing the network. The incident raised questions about the competence of grid managers to handle a transition away from fossil fuels as the opposition Labour Party argues in favor of taking parts of the system back into government hands.

“I’m not pointing the finger, I’m just saying I think it’s sensible to do a broad investigation,” Pettigrew told the FT.

For more on the London blackout, click here

A government investigation conducted by the Energy Emergencies Executive Committee will probe some of those issues. The inquiry will look into not just the actions of National Grid, but also how power cuts were prioritized, including to essential services, the Department for Business, Energy and Industrial Strategy said in a statement Wednesday.

The committee, a partnership between the government, the regulator Ofgem and industry, will file an interim report in five weeks and a full report within 12 weeks. Ofgem has also requested that National Grid provide an “urgent interim report” on the event by Friday.

National Grid rose 0.8% to 843.8 pence at 9:18 a.m. in London. The stock is down less than 1% since Friday’s blackout.