A temperature of 40.3C was provisionally recorded in Coningsby, in Lincolnshire, on Tuesday afternoon, beating the previous record for the UK of 38.7C in Cambridge three years ago, by 1.6C.
The Met Office said at least 29 observation sites across England have provisionally broken the previous all-time record, from Bramham, in West Yorkshire, to Charlwood, in Surrey.
In Doncaster, field fires led to road closures and disruption in Rossington, Hatfield, and Sprotbrough.
Images shared on social media were reminiscent of bushfires, showing flames ripping through fields leaving crops scorched and blackened.
South Yorkshire Fire and Rescue confirmed they were dealing with a number of field fires around the county, including one in the Rawmarsh area of Rotherham, as forces declared a major incident.
A spokesperson for South Yorkshire Police said: “The emergency services working across South Yorkshire have now declared a major incident due to the demand on services from fires across the county.
“The fires are being prioritised in relation to risk to life and risk to property.
A fence fire on the side of the M62 near Huddersfield closed lanes leading to three miles of congestion.
Humberside Fire and Rescue also declared a major incident in their control room yesterday evening and said crews were “responding to a high volume of 999 calls and fires across the Humber region during today’s record-breaking heatwave.”
And fifteen fire crews attended a large woodland fire in Nottinghamshire
Amid the sweltering heat a major incident was declared in London in response to a surge in fires across the capital.
Around 100 firefighters tackled a blaze in the village of Wennington, east London, on Tuesday afternoon, with television footage showing black smoke billowing into the air, with buildings and fields on fire.
Nigel Arnell, Professor of Climate Change Science, University of Reading, said the hot, dry and windy conditions meant the smallest spark could set off a fire.
He warned: "Climate change is increasing fire danger across the UK, and we need to be prepared for it."
Trackside fires and damage to overhead lines also halted train services, while there were widespread suspensions, disruptions, reduced services and temporary speed restrictions to cope with the risk of buckling rails.
The Prime Minister paid tribute to firefighters and frontline workers as they battled incidents across the UK.
Boris Johnson tweeted: "My thanks go to all the firefighters and frontline services who are working incredibly hard to keep us safe on this scorching day.
Heatwaves are being made more intense, frequent and longer by climate change, and scientists said it would be "virtually impossible" for the UK to have experienced temperatures reaching 40C without human-driven global warming.
Doncaster North MP Ed Miliband, Labour's shadow secretary of state for climate change, said that extreme hot weather like this will become the "new normal" under climate change.
He also warned that the Conservative Government has failed to prepare the UK for this type of weather.
"Reports of fires across the country are deeply distressing. We must do everything we can to support the families and communities affected. I urge everyone to stay safe and salute the courage of our fire services," he said.
One farmer told of how fallen sky lanterns almost led to a field fire.
Martin Stone, from Bingley, found 11 sky lanterns next to rows of dry hay bales on Tuesday morning and said they could have caused a devastating blaze.
He said: “If the hay had caught fire from the lanterns with their bamboo frame and wire - both hazards in themselves - the wind would have quickly spread it to other fields full of hay as well as our building half full of hay and machinery. It would also have endangered nearby properties.”
“I find it inconceivable that people, without any thought, can let these fire bombs go into the sky without knowing where they will land or what damage they could cause”