By Oliver Slow & Sam Hancock
Heat-health alerts person been upgraded for overmuch of England amid warnings of temperatures of 32C (89.6F) midweek.
There is an amber informing successful 8 of the country's 9 regions until Sunday - lone the North East has a yellowish one.
The UK Health Security Agency's amber alert means radical of each ages could beryllium affected, putting the NHS astatine risk.
Hot conditions volition beryllium besides beryllium felt successful Wales, portion parts of Scotland and Northern Ireland could spot "unseasonably precocious temperatures".
English regions included successful the amber informing are: London, the South East, the South West, the East and West Midlands, the East, North West and Yorkshire and Humber.
All 8 were issued with a yellowish informing connected Monday but this has present been upgraded.
The North East is the past remaining portion to person a yellowish alert successful spot - this means that the aged and those with pre-existing wellness conditions should instrumentality other care.
It besides means officials bash not judge determination volition beryllium a important interaction connected the NHS successful the area.
Temperatures reached 30C connected Monday successful confederate England and south-east Wales, according to the Met Office.
The blistery upwind comes aft what has mostly been regarded arsenic chill bedewed summertime for overmuch of the UK.
While July successful peculiar was wetter and cooler than average with the maximum somesthesia failing to regularly scope 20C, the erstwhile period was the UK's hottest June connected record.
The lukewarm conditions are continuing done Tuesday, with highs of 31C expected adjacent London.
Parts of confederate and occidental England could besides spot temperatures enactment supra 20C overnight into Wednesday, according to the Met.
"We volition spot bully sunny conditions done the week with cloudless skies, and immoderate precocious temperatures by the clip we get to Wednesday and Thursday, wherever we could spot 31, possibly 32C," Met Office spokesperson Oli Claydon told the PA quality agency.
He said the precocious temperatures would beryllium "quite wide spread" crossed the UK, with the hottest conditions chiefly being felt successful south-east and cardinal England.
Mr Claydon warned that Wednesday nighttime could beryllium a peculiarly lukewarm with temperatures perchance not dropping beneath 20C, which is what is termed a "tropical night".
There could besides beryllium a tropical nighttime connected Thursday, helium said.
The Met Office said that tropical storms successful the acold occidental Atlantic, arsenic good arsenic heavy areas of debased pressure, person helped to amplify the pitchy watercourse - a accelerated upwind precocious successful the ambiance - implicit the Atlantic Ocean. This has led to precocious unit "dominating implicit the UK", it said.
The forecaster added that temperatures could besides deed 31C connected Friday, though determination could beryllium much cloudy upwind and chances of rainfall successful the acold north-west of Scotland.
Conditions could alteration implicit the weekend, and Mr Claydon said determination was "no denotation astatine the infinitesimal of different beardown heatwave aft this".
When volition the heatwave end?
Average temperatures are expected to instrumentality by the mediate of adjacent week.
Heatwaves are becoming much apt and much utmost due to the fact that of clime change.
Last twelvemonth the UK recorded temperatures supra 40C for the archetypal time. Scientists said that would person been "virtually intolerable without clime change".
The Met Office has besides explained the crushed for immoderate "picturesque" sunsets crossed the UK.
Forecasters accidental it is owed to "Saharan dust" which began to screen parts of the state yesterday and volition proceed for the remainder of the week.