Thames Water said the new restrictions will come into effect from 23 July, but that customers in the affected areas should abide by the new rules straight away.
Households have been told not to use hosepipes for non-essential uses, such as watering gardens, cleaning cars, filling up paddling pools or topping up hot tubs.
The decision follows recent periods of record hot weather and increased demand.
Meanwhile, the Environment Agency's National Drought Group said parts of southern, central and eastern England have moved closer to drought status, classified as under "prolonged dry weather".
The third heatwave of the year has seen ponds and wetlands dry out, which will impact bird breeding, while some rivers have dried up in places, the EA said.
Wildfires have ripped through several areas, including dozens of delicate protected sites, and prime agricultural land, it added.
Eight areas across England are in "prolonged dry weather" - the stage before drought.
They are:
• East Anglia
• West Midlands
• Devon, Cornwall and Isles of Scilly
• Lincolnshire and Northamptonshire
• Hertfordshire and London
• Wessex
• Thames
• Solent and the South Downs
'Only 40% of average spring rainfall'
Thames Water said demand was currently around 10% above normal levels across the Thames Valley and Home Counties and 7% above normal in London.
In addition, it said the Thames Water region had only received 40% of average spring rainfall this year - with none so far in July within the Thames catchment area.
It is the latest in a string of hosepipe bans.
Bans are also in place for Southern Water customers in Hampshire and the Isle of Wight, Cambridge Water customers, Affinity Water customers in Bedfordshire, Berkshire, Buckinghamshire, Essex, Hertfordshire, Surrey, and Anglian Water customers in the East of England.
Met Office figures show that central and South East England have seen the longest unbroken spell of no recorded rainfall this century.
The forecaster warned that during peak periods, water had been used faster than it could be treated and moved through parts of the network, straining local supplies.
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'Difficult combination' of hot and dry weather
After Thames Water announced the latest hosepipe ban, Helen Wakeham, chair of the National Drought Group, said the hot conditions and lack of rain have made for a "difficult combination, and we are seeing the effects on our farmers, our wildlife, and the amount available for public and business use".
"All sectors are taking action," she said, "and we are grateful to the public for following the restrictions, where in place, to make sure there is enough water for everyone this summer.
"We want everyone to stay safe and hydrated during the hot weather but every drop we can save is a drop more for nature and agriculture."
'Customers using an extra 100 million litres every day'
Thames Water said earlier that customers were using an extra 100 million litres every day - equivalent to adding all the homes in Manchester to the network.
On Monday, South East Water said more than two million people face a hosepipe ban after it extended water restrictions.
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As well as pushing up demand as people consume more water, periods of hot weather can also lead to physical pressure on underground water pipes, leading to higher rates or bursts and leaks.
Thames Water stressed that it was repairing more than 750 leaks every week and continuing its biggest network upgrade in 150 years.
While the company said it plans for periods of dry weather and increased summer demand, it claimed the scale and duration of recent demand is having a "significant impact" on water resources.
The former Manchester United boss outlined his huge respect for Keegan, who died at the age of 75 after a battle with cancer.
Speaking to Track Radio, Ferguson, who was famously the target of Keegan's "I'd love it, absolutely love it, if we beat them" rant, said: "I had the utmost respect for him. We had many duels when he was manager of Newcastle, but I have to say the job he did at Newcastle was fantastic.
"He re-energised that club and he brought that enthusiasm and fanaticism that great supporters can give. That's the job he did.
"And he also brought three great players to the club - [David] Ginola, [Faustino] Asprilla, Philippe Albert - and added a bit of class to the team, and I must say the challenges we had with Newcastle at that time at United were huge.
"Kevin carried the love of the game on his sleeve, there's no question about that, and that carried right on to the fans, to the players.
"That period at Newcastle was of emotion, it was excitement. They brought these great players to the club too and they added to it, and it gave Newcastle - I think - their best ever team."
That emotion came out during a Sky Sports interview in April 1996 when the former England striker delivered an outburst as Sir Alex's United closed the distance with Newcastle - before ultimately beating them to the title.
But Ferguson revealed the pair bumped into each other at a pub a few weeks after the season had ended and spent the night around a piano together.
Ferguson said: "The great thing about him, he held no grudges. That was a fantastic quality he had and we had a great night.
"All aside whatever happened in previous weeks, that was soon forgotten. I really respected him for that."
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Keegan's death, announced on Monday, saw a range of tributes to the former Scunthorpe, Liverpool, Hamburg, Southampton and Newcastle player.
Sir Trevor Brooking, who played alongside him for England, said: "I am so very sad to hear the devastating news about my friend and former team-mate Kevin Keegan.
"My friendship with Kevin goes back many decades, to our playing days for England. We were lucky enough to develop a real understanding on the field of play and know what each other was thinking.
"Kevin liked to run and find space on the pitch and I'd try to time my passes to give him the best chance to use his world-class skills to score.
"We roomed together on England duty and Kevin, with his bubbly character, was never shy of making jokes, often at my expense!
"I recently met up for lunch with Kevin and Jean when they were visiting London. Although it had been a while since we'd last seen each other, we picked up our conversation as if it had been yesterday.
"That afternoon, reminiscing about our footballing days, is one I will always treasure.
"Our thoughts and love are with Jean, Laura, Sarah and all of Kevin's family at this sad time."
The mystery man was given the name Croft Man for the purposes of the inquest. His remains were discovered in the River Stour near Croft, part of the town of Sudbury, in August 2020.
Two mummified legs and feet and two mummified arms without hands in black bin bags were found by a dog walker.
Two days later, police divers found skull fragments, facial bones and two loose teeth in a thin blue plastic bag 150 metres further along the river.
Suffolk's senior coroner Nigel Parsley recorded that the Croft Man died from a "violent assault" at an inquest into his death in Ipswich on Tuesday.
The removal of the man's hands and the injuries to his head and face "appear to have been an attempt to hamper his identification," Mr Parsley said, adding it was "more likely than not the Croft Man was unlawfully killed".
Investigators have been unable to identify the man, despite searching national and international missing persons databases and looking into relevant criminal activity.
Radiocarbon dating suggested he was born before the early 1950s and died in about 2008 to 2012, so was probably in his late 60s to 70s when he died, the coroner said.
"We must remember that the Croft Man was somebody's son. He lived for 60 to 70 years. He may well have had family; he almost certainly had friends.
"It's a tragedy we cannot identify him as there must be some loved ones somewhere wondering where their loved one is."
Superintendent Mike Brown of Suffolk Police said DNA testing indicated the two sets of remains were the same person, thought to be a white northern European male, likely to have been born with blonde or light hair which may have darkened naturally, and blue or green eyes.
Identifying the victim is "the biggest challenge" detectives face, he said, adding that the bags were left at the site between 13 August and 19 August.
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Dog walker Julie Dunn-Beechin said in a statement read to the hearing that she saw two black bin bags in the water on a stretch of the River Stour by water meadows on 27 August, 2020.
She said her dogs began sniffing nearby and something "didn't seem right to me".
Park ranger Samuel Morgan, whom she called, said: "She said she didn't know if she had been watching too many Midsomer Murders and had a concern about what could be in the bags."
He said the bags had rocks and bricks in and "what looked like a Toilet Duck soap that had partly dissolved".
Mr Morgan said he saw "through a small hole in the bag what I thought looked like mummified skin and bone" and what appeared to be the ball joint of an arm, and he called police.
The vessel, which was shadowed by a Royal Navy ship, carried out the artillery manoeuvre south of Plymouth on Monday.
Moscow's warship, The Neustrashimy, has been escorting Russian 'shadow fleet' oil tankers through the English Channel.
A Ministry of Defence spokesperson said: "A Russian naval vessel shadowed by the Royal Navy conducted a live-fire weapons exercise in international waters approximately 40 nautical miles south of Plymouth yesterday.
"The Royal Navy monitored that exercise throughout, continues to track the vessel's activity closely, and stands ready to protect UK national security."
Mr Streeting told reporters on Monday: "We should see yesterday's events as performative and irresponsible.
"It's not the first time that Russia has behaved like this, and frankly, it's the tip of the iceberg of the daily threats that this country faces and our allies face."
He added: "Russia should be in no doubt about the resolve of this government and this prime minister."
Before the exercise, the Russian vessel informed HMS Tyne of its intention to conduct gunnery activity.
It then requested that HMS Tyne reposition to a safer distance, which it did.
The exercise was carried out in international waters and lasted for 30 minutes.
Dmitry Peskov, Vladimir Putin's spokesman, said: "All exercises and actions of our warships are carried out in strict accordance with international maritime law.
"Therefore, there is no need to see any hints here. But, in turn, of course, the arrival of the new UK Prime Minister, probably one of his first actions was the remark of unconditional support for Ukraine, therefore, about Britain's intention to keep doing everything for the war to continue. This is a fact, which we, of course, are noting."
This latest incident is the second Russian warship to escort a so-called shadow tanker through the Channel in recent weeks.
Sky News' helicopter tracked The Neustrashimy as it was refuelled in the North Sea by a Russian navy ship earlier this month.
Last month, its predecessor, Admiral Grigorovich, fired warning shots at a British couple sailing a yacht.
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That same month, the captain of another Russian shadow fleet tanker was detained by the UK and charged with contravening sanctions.
Royal Marine commandos and NCA officers landed from a Chinook helicopter and seized the tanker in the Channel 25 miles south of the Isle of Wight.
Earlier in June, the French navy aided by British forces, intercepted another oil tanker under international sanctions that was coming from Russia.
In March, the UK helped the French navy seize another vessel, a Mozambique-flagged ship called the Deyna, in the Mediterranean.
It was sanctioned by the UK and the European Union for its role in shipping Russian oil.
The same month then-PM Sit Keir Starmer allowed British forces to seize shadow fleet vessels, leading the ships to veer way from the English Channel.
Joshua Robbins, 23, died on 29 January after falling five floors from the communal landing outside his father's flat in Newton Street, London.
He went to see if the pizza they ordered had arrived, and leaned over the railings, which then gave way. His father, Will Robbins, 49, watched his son fall to his death.
St Pancras Coroner's Court heard during a pre-inquest review on Tuesday that the Metropolitan Police is now carrying out a corporate manslaughter investigation in relation to Mr Robbins's death.
Islington and Shoreditch Housing Association is complying with requests for material, the court also heard, and the Met Police is liaising with the Crown Prosecution Service in the investigation.
The pre-inquest review also heard from Detective Inspector Mark Paterson, who said the scene of Mr Robbins's death was examined at the time and a forensic engineer attended.
DI Paterson said: "It's an ongoing investigation, a lot of the material is held by ISHA who are fully compliant with requests that are being made at this stage."
CCTV has also been obtained. Senior coroner Mary Hassell scheduled another pre-inquest review for 6 January 2027.
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Fiona Garrett, Joshua's mother, previously told Sky News that she has since set up No More Falls, a campaign calling for mandatory safety standards for high-rise buildings that "have these set-ups, or window boxes, balconies".
She told The UK Tonight With Sarah-Jane Mee in March that her son's death has "to mean something, he can't just disappear and have no reason behind it".
The 46-year-old, originally from Essex, sent an email to her son's local MP, the former prime minister Sir Keir Starmer, requesting a meeting as part of her campaign for justice.
"I want people to actually understand that this isn't going to go away," she said to Sky News. "I don't want to hear 'lessons learnt', I don't want to be palmed off with nonsense, I want to see actual action.
"That's the least I deserve; our family deserves that. Joshua's life mattered, so his death matters even more."
Pippa Fleetwood-Read, chief executive at Islington and Shoreditch Housing Association (ISHA), which manages the site, gave Sky News a statement at the time.
She said: "Joshua's tragic death at the end of January has been deeply distressing for everyone who knew him. We know his death has had a profound effect on his parents, family, friends and neighbours - and we offer our heartfelt and sincerest condolences to them at this incredibly difficult time.
"We are doing everything we can to support everyone living at Holland and Thurstan Dwellings, including offering counselling support, having a daily on-site presence, including a dedicated officer visiting twice weekly to listen directly to any concerns they may have. We are keeping the residents informed by sending a weekly written update."




