FLAMES leaping 100ft into the air were seen when a Forest Hill electricity substation caught fire this morning.

The blaze has left thousands of homes without power in the News Shopper area including in parts of Forest Hill, Lewisham, Penge and Bromley.

Traffic lights have also been affected by the power cut.

Six fire engines were called to deal with the flames which are believed to have been visible from the Blackwall Tunnel at the height of the blaze between 7am and 8am.

Southern train services are being diverted because of the fire and tickets are being accepted on local bus routes.

Services to West Croydon from London Bridge are cancelled and services to Caterham are being diverted and will not call at stations between New Cross Gate and Sydenham.

Philip Venier witnessed the incident from his house near to the substation in Sydenham Park Road.

He said: "There was a massive rumbling noise and I first thought it was a heavy roller because Thames Water is doing work.

"Then there was a bang and then some yellow flashes coming up then there was a massive flash where the generator had short circuited and then the fire started."

The 45-year-old says the firefighters arrived within 10 minutes but had to wait for specialist equipment before they could tackle the blaze.

He says they used foam and water to put out the flames after the electricity supply was shut off.

The PE teacher added: "It was quite a spectacle.

"I reckon there were about 100ft flames.

"You could see the flames from the Blackwall Tunnel and the smoke was thick.

"Somebody else drove from Catford and said the lights are out and it is chaos."

Southern train services are being diverted because of the fire and tickets are being accepted on local bus routes.

Services to West Croydon from London Bridge are cancelled and services to Caterham are being diverted and will not call at stations between New Cross Gate and Sydenham.

An EDF Energy spokesman said: "A fire at one of our substations is affecting power supplies to customers in parts of South East London.

"Supplies were isolated for safety reasons at 8.51am. London Fire Service, along with EDF Energy Networks staff, are on site.

"We are unable to confirm how many customers are affected at this stage.

"We are liaising closely with the fire service and do apologise for the inconvenience this is causing customers.

"Once London Fire Service have allowed access to the affected area, we will be able to assess the damage.

"We hope to restore supplies as quickly as possible."

It is not yet known when power will be fully restored or when the trains will be back to normal.