Commuters face a day of chaos after a signal failure left the network in chaos.

Passengers travelling from Brighton and Sussex are being told to avoid travel to London Victoria, and to expect long delays.

At the station this morning passengers are being told that services have been hit because of a power failure near Streatham Common.

Gatwick Express services have been suspended, while Thameslink and Southern services are badly affected.

National Rail said the disruption is expected to continue until the end of the day and has advised passengers not to use those operators for travel from the south into the capital.

The problem with signalling equipment was discovered at 10.30pm on Wednesday and Network Rail engineers have been unable to fix it despite working overnight.

A Network Rail spokesman said: "Owing to a loss of signalling at Streatham Common, services are being disrupted to and from London Victoria.

"The signal loss means we are unable to run services between Balham, Selhurst and Haydons Road.

"We have had engineers working on site overnight doing all they can to fix the problem. However, we anticipate that the signalling will not be up and running this morning.

"We apologise for the inconvenience caused by the fault and passengers are being advised not to travel with Thameslink, Southern or Gatwick Express from the south into London this morning."

The line is the country's second busiest, and dozens of trains have been cancelled.

Rail bosses say they are attempting to put on replacement bus services at key locations, in particular to get children to school.

Thameslink passengers have already suffered weeks of disruption following the introduction of new timetables on May 20.

Frustrated passengers have shared images on social media of travel disruption and packed carriages.

Social worker Jessica Edwards, 34, told the Press Association she paid hundreds of pounds extra per year to travel on the Gatwick Express from Hassocks in to Victoria, only to find the trains were often overcrowded due to cancellations on other services.

She said today's problems had meant arriving an hour late to work, adding: "I have had to get off at London Bridge and get a bus to Hackney. It's taking ages. All the stations are mobbed so it's not even worth trying to get the Overground or Tube."

Some passengers expressed anger after turning up at stations to find they were closed, despite rail apps stating some services were running.

Twitter user @VHC88 posted: "@SouthernRailUK your services are a total shambles. Carshalton station has been closed all morning and yet your app says services are running. Bus and Tube it is this morning."

Another passenger, Philip Keeler, wrote: "So Southern advise not to go to work? Southern are ruining the country for people and business.

"Can you imagine if a hospital said we have no power, everyone go home?"

There were long queues for buses as many passengers attempted to travel from closed railway stations to the unaffected London Underground network.

Some also complained that they were being asked to pay for bus travel.

Amelia Howard posted on social media: "@SouthernRailUK can you tell buses to accept train tickets as the whole of Carshalton station is closed.

"Just been told by bus (157) driver (who was very rude) I can't use it and I've paid £2k for my train ticket! Absolutely ridiculous."