Bus drivers have said that extreme heat, which has caused cab temperatures to reach 40C during heatwaves, are making it unsafe for them to drive.

More than 1,500 Arriva North London drivers have launched 26 days of strike action because they feel their health and public safety are being put at risk.

Workers have reported that current air-cooling systems just push hot air around instead of cooling the cab, with many buses not fitted with air conditioning.

One driver noted that the inside of the cab feels hotter than being outside.

Spending hours in the heat has caused some drivers to suffer from heat exhaustion, dizziness, migraines and dehydration.

Footage posted on social media shows nurses belonging to the Royal College of Nursing (RCN) have joined drivers on the picket line.

The bus strikes in north London which have started today involve Unite members employed by Arriva London North.

Walkouts are affecting garages at Barking, Edmonton, Enfield, Grays, Palmers Green, Stamford Hill, Tottenham and Wood Green.

Bus drivers are striking over working conditions during hot weather, with reports of cabs reaching up to 40C during a heatwave.

Arriva has said the hot weather has created complex challenges across the city’s bus network, but reiterated that the wellbeing of staff and passengers is its top priority.

Bus routes affected by the strike are: 19, 29, 34, 41, 66, 67, 76 (24hour), 102 (24hour), 103, 121, 141, 149 (24hour), 150, 158 (24hour), 175, 191, 192, 217, 221, 243 (24hour), 248, 254, 259, 279, 307, 313, 329, 341 (24hour), 349, 370, 375, 377, 616 (term time only), 675 (term time only), N19, N29, N41, N279, SL1, SL2, W3, W4 and W6.

Affected night services will operate as normal, on the nights before strike action starts.

Customers can check the latest service information using the TfL Go app.

A signalling system fault between Streatham Common and Selhurst is causing disruption to rail services this morning.

The fault means fewer trains are able to run through the area, with passengers warned that services may be cancelled, revised or delayed by up to 20 minutes.

The disruption is affecting a wide range of routes across south London, including services between Watford Junction and East Croydon, as well as trains from London Bridge towards Selhurst and East Croydon.

Services from London Victoria are also affected, including those running towards Selhurst, Sutton, Epsom Downs, Reigate and East Grinstead, alongside longer-distance services to Littlehampton, Bognor Regis, Portsmouth Harbour, Eastbourne, Hastings and Ore.

The disruption is currently expected to continue until 12pm.

Passengers travelling through the affected area are advised to check their journey before setting off and allow additional time for travel.

The former chairman of the Strategic Rail Authority said investigators should be able to see “what the track looked like as the train arrived”.

Richard Bowker told BBC Radio 4’s Today Programme that the Rail Accident Investigation Branch will “be looking at things like the condition of the track”.

He added: “We’ve seen images of damaged track – was that caused by the derailment, or did it cause it, or a bit of both? They’ll look at the effects of heat.

“The train itself I would expect to be fitted with forward-facing CCTV cameras, so it will be possible to see, I would suspect, what the track looked like as the train arrived.

“They will be able to download data from the train. It has like a black box. They’ll know what speed it was going. They will know if there were any braking applications.”

Drivers are striking because temperatures inside their bus cabs are soaring past 40C during summer heatwaves, which have been relentless in the capital this year.

The union states that current air cooling systems merely push around hot outside air, turning cabs into dangerous "greenhouses".

Workers are demanding that employer Arriva retrofits all affected vehicles with proper, functioning air conditioning to prevent heat exhaustion and protect safety.

Arriva has reiterated that the safety and wellbeing of its staff and passengers is its top priority.

Wasim Mohammed, the managing director of Arriva London, explained that extreme summer heat is creating complex challenges across the city's bus network.

Footage shared on social media shows bus drivers on strike and standing at the picket line outside Stamford Hill Bus Garage this morning.

The strike has been called by Unite the union and will effect garages in north London.

Garages impacted are: Barking, Edmonton, Enfield, Grays, Palmers Green, Stamford Hill, Tottenham and Wood Green.

Images of the track where a train derailed just outside of Lewes station yesterday appears to show a bowed section.

The RAIB are on the scene to establish the cause of the derailment.

The Rail Accident Investigation Branch has arrived at the scene in Lewes where a train derailment took place yesterday.

A van could be seen close to the Landport area of Lewes in East Sussex.

The RAIB will carry out the the investigation into what happened.

Southern says the line will be blocked until the investigation has been concluded.

No timetable has been given for when the railway will be able to “safely reopen” after the derailment near Lewes, Network Rail has said.

Lucy McAuliffe, Network Rail route director for Sussex, told a press conference: “This is an evolving and complex situation.

“We will provide updates as soon as we have a clear understanding of the recovery work required and when the railway can safely reopen.”

She urged passengers to check before they travel.

She added: “I can only apologise to everyone who has been impacted by this incident but I also must thank the local response teams and community for everything they have done to support the response to this situation.”