AWG's annual profits tripled last year

AWG did not name the potential suitor and added that there was no certainty that an offer would be made.

The Anglian Water business serves about six million customers in the east of England and Hartlepool.

AWG also owns support services group Morrison, which works in the water, gas, electricity and telecoms sectors.

AWG employs about 9,000 staff across the UK.

Sector boost

Water companies, and other utilities such as power firms, are seen as attractive bid targets as they offer steady and predictable earnings to investors.

See AWG's share price

In May, AWG said annual profits had tripled to �109m in the year to April, helped by a combination of price rises and dry weather boosting demand.

AWG's shares were up 11.1% at 1514 pence by mid-morning, having earlier risen as much as 12.9%.

The news also lifted shares in other water companies, with Northumbrian Water up 4.4% and Kelda Group 3.5% higher.

Analysts said that competition regulations made it unlikely that another water company would offer to buy AWG, though they did not discount further offers coming in from investment companies.