By Daily Mail 18:06pm 18th July 2006

Water tankers have been drafted in to top up diminishing reservoirs as temperatures continue to climb towards 102f today.

As most of Britain prepares for what is expected to be the hottest day on record, water company Severn Trent has called in emergency supplies after households in Mansfield, Nottinghamshire, were left without water overnight.

It comes just hours after National Grid warned that the sweltering temperatures could lead to widespread power cuts.

Matt Wildsmith, from Severn Trent, said clean water reservoirs were emptying fast thanks to the hot weather as consumption increased by 200 million litres a day - the equivalent of supplying an extra 800,000 people.

But the company thinks the extra water is going on gardens and has asked residents to think twice before they turn on a hosepipe or sprinkler.

"We have seen very high levels of overnight usage which could indicate some people are leaving sprinklers running through the night," Mr Wildsmith said.

"Because of the huge increase in demand, water is being taken out of the system faster than we can put it in.

"This is a short-term problem and we are working to address the situation as quickly as possible. In the meantime, we are asking people to help us out and to use water sensibly.

"A sprinkler uses the same amount of water in just an hour as a family of four uses in a day."