Drought has forced seven water companies to introduce water restrictions today, affecting about 20 million people across southern and eastern England.

The move comes after parts of the country being declared in drought following the driest spell since 1976.

Thames Water, Southern Water, South East Water, Anglian Water, Sutton and East Surrey, Veolia Central and Veolia Southeast are bringing in the hosepipe bans, and other companies may follow if the dry weather continues. The firms say the bans are necessary to preserve essential water supplies and protect the environment.

Any customer defying the hosepipe ban will face a fine of £1000.

The main cause of the drought is two exceptionally dry winters which have not restocked supplies for the water companies.

Peter Simpson, the managing director of Anglian Water, said:

"Two dry winters have prevented rivers, reservoirs and aquifers from refilling with the water we treat and supply the rest of the year, especially during the hotter months when demand rises."

Martin Baggs, the chief executive of Thames Water, said:

"Imposing restrictions on the use of hosepipes, although regrettable, is the most sensible and responsible next step in encouraging everyone to use less water so we can maintain supplies for as long as it stays dry, and reduce the risk of more serious restrictions later in the year."

In face of the drought the water companies will be focusing on fixing leaks, moving water resources from wetter to drier areas and encouraging water saving measures by customers.

According to Ofwat water companies across England and Wales leaked more than 3.3billion litres a day in 2010/2011, with Anglian Water and Southern Water being the main culprits.

To help with water supplies, Thames Water is running its desalination plant at Beckton throughout the summer.