The source of the UK's River Thames has dried up for the first time on record against a backdrop of hosepipe bans and warnings of more high temperatures to come.
The famous river has moved eight kilometres downstream from its official starting point, outside the south-west English market town of Cirencester.
“Under our changing climate we can anticipate the frequency and severity of such periods of drought and water scarcity to intensify, with increasing competition for a dwindling resource and devastating impacts on aquatic life," Dr Rob Collins, director of policy and science at the UK's Rivers Trust, told The Guardian newspaper.
The driest eight-month period from November 2021, for the country since 1976, combined with record-breaking temperatures in July, have left rivers at exceptionally low levels, depleted reservoirs and dried out soils.
Parts of England have experienced the driest July since records dating back to 1836 began.
All of this has put pressure on the environment, farming and water supplies and is fuelling wildfires.
The Met Office has given a warning that there is "very little meaningful rain" on the horizon for parched areas of England as temperatures are set to climb into the 30s next week ― although forecast a return to more favourable conditions by the middle of the month.
While it could mean another heatwave — when there are above-average temperatures for three days or more — it is likely conditions will be well below the 40°C recorded in some places last month.
The situation has prompted calls for action to reduce water consumption to protect the environment and supplies, and to restore the country's lost wetlands "on an enormous scale" to tackle a future of more dry summers and droughts.
The call has been heeded by two of the UK's private water companies to date.
The Southern Water utility announced the move from Friday for customers in Hampshire and on the Isle of Wight, while the measure will follow in exactly a week for South East Water customers in Kent and Sussex.
Southern Water asked customers to limit use "to reduce the risk of further restrictions and disruption to water supplies, but more importantly to protect our local rivers".
South East Water said it had been "left with no choice but to restrict the use of hosepipes and sprinklers" from midnight on August 12 within Kent and Sussex "until further notice".
The company added that it was taking the step "to ensure we have enough water for both essential use and to protect the environment" and to enable a reduction in the amount of water "we need to take from already stressed local water sources".
Other water firms have so far held off bringing in restrictions despite low water levels, though some say they may need to implement bans if the dry weather continues.
Householders who have not yet been hit by restrictions are being urged to avoid using hosepipes for watering the garden or cleaning the car.
Thames Water's desalination plant, at Beckton, east London, which was built to deliver up to 100 million litres of water a day in dry weather events, is currently out of service.
UK drought — in pictures
Nature campaigners have criticised water companies for leaving it to "the last possible moment" to bring in restrictions, when rivers are in a "desperate" state, and for last-minute announcements that spur an increase in water demand before hosepipe bans come in.
Mark Lloyd, chief executive of The Rivers Trust, said: "Every year we get to this perilous position and at the last possible moment, when the rivers are at their lowest, we get discussion of temporary use bans.
"Announcing it at the last minute causes people to rush to wash their cars and fill their paddling pools, wash the dog, and causes an increase in demand before the ban comes in.
"This should happen before the rivers come to a desperate condition and there's not enough water for wildlife."
The Rivers Trust is calling for accelerated metering, rapid reductions in leakages and support for households to reduce water usage, through means such as installing low-flow toilets and rain-harvesting tanks.
Other methods include protecting wetlands and introducing permeable paving to build up local stores of water underground.