It's official - this week's hot weather in Hertfordshire has broken previous county records.

According to data from the Met Office and Norwich-based forecaster Weatherquest, the mercury hit 39.2C in Buntingford in East Herts yesterday (Tuesday, July 19).

The new Hertfordshire record is higher than the previous UK record - 38.7C - which was recorded at Cambridge University Botanic Garden on July 25, 2019.

Elsewhere in the region, John Davis, a weather enthusiast in Harpenden, recorded 38C at around midday.

The University of Hertfordshire observatory in Bayfordbury, between Hertford and Hatfield, recorded a maximum temperature of 38.9C at 3.20pm.

The mercury hit 39.6C at Woburn in Bedfordshire. The highest recorded temperature in the East of England now stands at 39.9C - recorded at the National Institute of Agricultural Botany, Cambridge and at Wittering, both in Cambridgeshire.

In London, 40.2C was jointly recorded St James's Park, next to Buckingham Palace, and Heathrow Airport - just 12 miles from Maple Cross in Hertfordshire.

The new UK record was set at RAF Coningsby, Lincolnshire, according to the Met Office, where a reading of 43.3C was recorded.

Dr Nikos Christidis, a climate scientist at the Met Office, said the UK could see highs of 40C or more every 15 years by the year 2100.

Dr Christidis said: "In a recent study we found that the likelihood of extremely hot days in the UK has been increasing and will continue to do so during the course of the century, with the most extreme temperatures expected to be observed in the southeast of England.

"Climate change has already influenced the likelihood of temperature extremes in the UK.

"The chances of seeing 40C days in the UK could be as much as 10 times more likely in the current climate than under a natural climate unaffected by human influence."

The Met Office has been responsible for keeping public weather records since April 1914.

The longest-running temperature record in the world is the Central England Temperature record, covering the Midlands and North West, which dates back to 1659.

According to climate scientists at the Met Office, 40C heat usually only occur once every 100-300 years.

Hundreds of Hertfordshire residents visited splash parks and outdoor pools throughout the county to make the most of the hot weather.

But the unusual temperatures brought disruption to commuters in the county, with all Thameslink and Great Northern trains cancelled north of London.

A line-side fire at Harrow forced rail firms to suspend trains between London Euston and Watford Junction in the late-afternoon.

Secretary of State for Transport Grant Shapps, who also serves as MP for Welwyn Hatfield, admitted it would take "decades" to upgrade travel infrastructure so that it withstands higher temperatures.

Mr Shapps told Sky News: "We're going to see this more regularly.

"We're going to see this more - because there's huge infrastructure to replace."

Hertfordshire Fire and Rescue Service declared a "major incident" following several serious fires in the county.

In one of the largest incidents in the county, 12 firefighting units were summoned to a field fire at Codicote, near Welwyn.

Five units were sent to a large vehicle fire on the M1 between Watford and Luton, while six units extinguished a combine harvester fire at Buntingford.

According to the Met Office, temperatures in Buntingford and the rest of Hertfordshire are set to become much cooler.

Rain is expected to hit the county in the evening, while eastern portions of Hertfordshire are covered by a yellow weather warning for thunderstorms.

Overnight temperatures are expected to sit around 18C, with a cooler and cloudier 23C heat throughout Thursday and Friday.

Sunshine is expected once again on Sunday, July 24 and Monday, July 25.