* JLR closes Solihull plant after request from water company
* Khan blasts water outages as "unacceptable"
* Temparatures return to normal after cold snap (Adds details of JLR plant closure)
By Elizabeth Burden
LONDON, March 5 (Reuters) - Burst water mains caused by a thaw in Britain's freezing temperatures closed a Jaguar Land Rover car plant in central England on Monday and left tens of thousands of people without water.
London's mayor Sadiq Khan said it was "unacceptable" that thousands across the British capital had no water, as utility companies struggled to maintain water supplies.
The worst snowstorms in Britain for nearly 30 years froze water in pipes last week, water suppliers said, during a blast of Siberian cold dubbed "the Beast from the East" which ground planes, stopped trains, blocked roads and shut schools.
Carmaker Jaguar Land Rover (JLR) halted production at its Solihull car plant near Birmingham, as water firm Severn Trent said it was targeting its supplies to keep schools and hospitals in central England open.
"Due to a water shortage caused by a burst water main, we have had to stop production this afternoon," a spokeswoman for JLR said.
Severn Trent said that it was working with other big businesses in the area on limiting water consumption. Production at Mondelez-owned chocolate company Cadbury's Bournville plant was also halted, the BBC said.
At least 23,800 households, including 12,000 households in London, were left without water when pipes burst after temperatures rose and snow thawed, prompting suppliers to advise customers not to waste water.
"It is unacceptable that thousands of Londoners remain without water this morning," Khan said on Twitter. "I have sought assurances from Thames Water that they are doing everything possible to fix the problems and get the supply switched back on for everyone."
At a supermarket in Balham, south London, Thames Water employees distributed crates of bottled water to a waiting queue of people, while in Hampstead to the north of the capital, they ferried crates to residential streets in their own cars.
Suppliers warned disruption would continue as they worked to fix leaks and refill pipes and Thames Water advised its 15 million customers to cut their usage.
"Where possible, take short showers rather than baths, do not leave taps running unnecessarily and only run washing machines and dish washers when you have a full load," the company said in a statement on its website.
Severn Trent, a supplier of water to 4.3 million homes and businesses in the middle of England, said the number of burst pipes was up 4000 percent, while in Wales, Welsh Water said "unprecedented challenges" had affected 4,500 homes.
Farther north, Scottish Water said there was no significant impact on its customers because Scotland had not suffered the same rapid thaw. (Additional reporting by Sarah Young; writing by Alistair Smout editing by Michael Holden)