Significant parts of England and Wales have been hit by a massive power outage. British media reports say the situation has caused chaos on trains and subways, with citizens trapped underground.

It is also reported that many traffic lights in London are out of order.

"We are aware that power shortages have affected large areas of London and the South East. We believe it is a fault in the National Grid (power company) network, which is affecting our customers, �reads the response from the British Power Network.

WPD, the operator of the Midlands, Southwest and Wales power distribution network, says it is a "major incident".

London's train service, including Thameslink and Gatwick Express, is facing delays and cancellations. The National Railway reports that a large number of train services have been affected by the blackout.