On Wednesday, drivers at Arriva North London’s Tottenham garage told the World Socialist Web Site that even when the “air-cooling” system is on, temperatures inside can reach 39 to 40 degrees Celsius.

The update is likely to cause major disruption.

Passengers have been warned of major disruption to bus journeys over the coming months as drivers are set to walk out over a heatwave row. Bus services in North London and Essex could be thrown into ...