Power giant rapped over blackouts

Thousands of London commuters were left stranded

The National Grid has escaped a fine over two power failures that affected nearly half a million people.

Regulator Ofgem blamed poorly installed equipment for the blackouts in London and Birmingham in August and September.

But on Friday the watchdog warned the firm that similar failures could lead to multi-million pound penalties under a planned incentive scheme.

The first power cut caused 60% of the London Underground network to close, stranding 250,000 rush hour passengers.

'Some mistakes'

Thousands of people were stuck in tunnels when trains ground to a halt on 28 August.

About 270 sets of traffic lights were out in many areas, causing confusion on the capital's roads.

The following week saw another 220,000 National Grid customers affected by a power failure in east Birmingham that lasted for 42 minutes.

Ofgem set out the results of its inquiry on Friday, which found that the blackouts were caused by a series of unrelated events "some of which were the result of mistakes by National Grid".

The watchdog did not impose a fine because it said the firm had not breached its legal obligations.