So often cast as the villain, the UK's big supermarket chains turned heroes this week as they put themselves at the heart of emergency efforts to ensure people affected by this week's severe flooding were kept supplied with water.

About 350,000 residents of Gloucestershire lost their running water as a result of water contamination at treatment facilities in the area. Supermarkets throughout the county offered donations and the use of their car parks as a base for distribution.

Tesco said it was supplying 2.5 million litres of bottled water a day - divided between extra stocks for sale in stores and donations to those most in need.

Rival chain Asda, meanwhile, donated 52,000 litres of bottled water to Gloucester's Red Cross centre on Tuesday and pledged donations of clothing, blankets, torches, batteries and camping chairs.

It also chartered two 16,000-gallon water tankers from Yorkshire Water to supply its Gloucester store and the Red Cross centre.

Sainsbury's said it was donating one million litres of bottled water to residents in Gloucestershire.

Besides water, it was also keeping stores in the flood-hit areas well-stocked with baby products. Morrisons, meanwhile, said high levels of water stocks were maintained at stores in the worst-affected areas.

In total, Severn Trent water said it was receiving between 4.5 and five million litres a day from retailers, and that this arrangement would continue until 4 August at least. Andrew Marsh, public affairs manager at Severn Trent Water, praised retailers for their quick response.

"They have been fantastic and have been, to a large degree, flexible through the water purchasing agreement. It is times like this when the sense of partnership really comes through."

Bottled water manufacturers also did their bit. Major suppliers, including Britvic, Danone Waters UK and Coca-Cola Enterprises, reacted quickly to the crisis by donating more than a million litres of water.

Richard Laming of the British Soft Drinks Association said: "When something happens on this scale, everyone has to do their bit. Sources of bottled water are proving to be a vital natural resource."