Bus drivers in north London could strike over hot working conditions, causing major disruption for commuters.
It comes after last week’s heatwave saw records for London’s hottest June day broken as temperatures climbed to 36.4C.
More than 1,900 drivers across ten Arriva North London garages will be balloted on strike action.
The affected garages are Barking, Clapton, Dartford, Edmonton, Enfield, Grays, Palmers Green, Stamford Hill, Tottenham and Wood Green.
If the strike goes ahead, it could cause severe disruption and delays on the north London network.
Unite claims Arriva failed to act on complaints from drivers about working conditions during the hot weather.
The union also argues that air cooling systems on the buses are not sufficient, as the reduction in temperature onboard buses was only two or three degrees, rather than the usual maximum of ten, during the recent hot weather.
Officials claimed issues with the cooling systems had been raised with Arriva in recent years but no action had been taken.
Demands from drivers include the installation of air conditioning.
The ballot runs from July 1 and July 29.
Unite general secretary Sharon Graham said: "Bus drivers have suffered in these scorching temperatures for long enough and the situation is getting worse.
"Arriva must stop putting profits before people and invest in much better systems to keep buses cool. Our members there have Unite’s full support in their fight for decent working conditions."
Unite regional officer Steven Stockwell said: "Arriva has failed to provide our members with a safe and comfortable working environment during the hot weather. This is putting bus drivers and passengers at risk and our members believe they have no choice but to ballot for industrial action.
"We recognise that those who use these bus services may be frustrated to hear this news, but this is a serious safety issue. It is on Arriva to create a safer environment, not just for our members but the general public and it must do this immediately or face disruption."
A spokesperson for Arriva London said: "We’re aware that Unite plans to ballot its members about industrial action.
“We will continue to work with Unite and try our best to find a resolution."
