A heat health alert has been extended for 24 hours as the Met Office issued an amber weather warning.
The alert for extreme heat across Thursday, Friday, Saturday and Sunday comes with temperatures set to soar.
It covers large parts of the UK including the East Midlands, East of England, West Midlands, South East England, North West England, South West England, Yorkshire and Humber and Wales.
It follows the first ever red warning issued last month, when temperatures in parts of the UK exceeded 40C for the first time.
The UK Health Security Agency have also issued a level-three heat-health alert to apply from Tuesday to Saturday.
The Met Office confirmed: "With high temperatures now forecast to last throughout the weekend, the UK Health Security Agency has extended the current heat health alert.
"The alert is now in place from midday Tuesday 9 August until 11pm Sunday 14 August.
"The public are urged to look out for family, friends and neighbours who may be more vulnerable during prolonged periods of hot weather – particularly elderly people who live alone and people with underlying health conditions."
Last month was the driest since 1935 and four regions have been hit by a hosepipe ban.
Hosepipe bans are in force in Hampshire and on the Isle of Wight. On Friday, others are due to come into force in Kent and Sussex.
Earlier, a warning was sounded for everyone to remain vigilant as they may experience sunburn or heat exhaustion and other heat-related illnesses.
There is an increased risk of water safety and fire-related incidents and a warning for those likely to visit coastal areas, lakes, rivers and other beauty spots.
The UK Health Security Agency has already issued an amber alert covering southern and central England from noon on Tuesday until 11pm on Sunday, with experts advising people to look out for those who are older or with existing health conditions, as well as young children.
Dr Agostinho Sousa, head of extreme events and health protection at the UKHSA, said: "We want everyone to enjoy the warm weather safely when it arrives but remember that heat can have a fast impact on health.
"It’s important to ensure that people who are more vulnerable – elderly people who live alone and people with underlying health conditions – are prepared for coping during the hot weather.
"The most important advice is to ensure they stay hydrated, keep cool and take steps to prevent their homes from overheating."
Regions covered in the Amber Weather Warning
East Midlands
- Derby
- Derbyshire
- Leicester
- Leicestershire
- Lincolnshire
- Northamptonshire
- Nottingham
- Nottinghamshire
- Rutland
East of England
- Bedford
- Cambridgeshire
- Central Bedfordshire
- Essex
- Hertfordshire
- Luton
- Norfolk
- Peterborough
- Southend-on-Sea
- Suffolk
- Thurrock
London & South East England
- Bracknell Forest
- Brighton and Hove
- Buckinghamshire
- East Sussex
- Greater London
- Hampshire
- Isle of Wight
- Kent
- Medway
- Milton Keynes
- Oxfordshire
- Portsmouth
- Reading
- Slough
- Southampton
- Surrey
- West Berkshire
- West Sussex
- Windsor and Maidenhead
- Wokingham
North West England
- Cheshire East
- Cheshire West and Chester
- Greater Manchester
- Halton
- Warrington
South West England
- Bath and North East Somerset
- Bournemouth Christchurch and Poole
- Bristol
- Cornwall
- Devon
- Dorset
- Gloucestershire
- North Somerset
- Plymouth
- Somerset
- South Gloucestershire
- Swindon
- Wiltshire
Wales
- Blaenau Gwent
- Caerphilly
- Cardiff
- Merthyr Tydfil
- Monmouthshire
- Newport
- Powys
- Rhondda Cynon Taf
- Torfaen
- Vale of Glamorgan
- Wrexham
West Midlands
- Herefordshire
- Shropshire
- Staffordshire
- Stoke-on-Trent
- Telford and Wrekin
- Warwickshire
- West Midlands Conurbation
- Worcestershire
Yorkshire & Humber
- North Lincolnshire
- South Yorkshire
- West Yorkshire
