AWG, which owns Anglian Water, announced an agreed 1,555-pence-per-share takeover by Osprey Acquisitions, an investment consortium comprising Canadian and Australian pension funds, as well as British venture capital firm 3i.

However, in a separate statement issued later, AWG added that it had also receiver approaches from "certain third parties" which "may or may not lead to another offer being made".

Osprey meanwhile said it bought 16.3 million AWG shares on Monday, taking its total stake to 12.473 percent.

In reaction, AWG saw its share price surge 4.66 percent to 1,617 pence, while London's second-tier FTSE 250 index, on which the company's stock is traded, won 0.21 percent to 10,017.70 points.

AWG is a water services and infrastructure group and employs 9,000 staff across Britain. The company's Anglian Water division serves around six million customers in eastern England.

In the same sector on Monday, Australian investment fund Hastings announced that it had bought South East Water for around 665.4 million pounds.

South East Water operates in southern England and provides water to a population of nearly 1.4 million.

Hastings said it intended to merge the company with Mid Kent Water, which it bought last year, subject to a review by competition authorities.

Meanwhile, German power giant RWE had recently confirmed that it was seeking to either sell or float Thames Water, which is Britain's biggest water supplier with about 8.5 million customers.

Thames Water has been blighted by criticism for failing to plug leaks from its ageing underground pipes, particularly as the region around London is experiencing its worst drought for a century.