Blackout report will take weeks

The cause of the London blackout that trapped thousands on the Tube will not be known for weeks.

Ministers have called executives from the National Grid and power companies for talks but a final report on the causes will not be finished until the end of the month.

Energy Minister Stephen Timms told MPs that the most likely reason was a faulty transformer and a mains supply cable.

Both burned out within minutes of each other, causing other lines to blow. But Mr Timms said investigators had ruled claims that blame lay with under-investment or a shortage of power generators.

The power cut, covering south-east London and parts of Kent during rush hour on 28 August, affected 410,000 homes and offices.