Britain's electricity and gas networks have announced they will merge to create a £14.8 billion sterling group that can push into the United States.
National Grid Group, monopoly bulk electricity carrier in England and Wales and a significant US player, is to buy the owner of the Transco UK gas network, Lattice Group, for about £6.3 billion.
Some £14.3 billion of combined debt will give the business an enterprise value of almost £30 billion - making it Britain's biggest utility. The deal sent shares in both companies up in early trade, with Lattice up as much as 12 per cent.
Both companies are feeling the financial pinch and expect the deal to save them £100 million a year.
National Grid has seen a dramatic slide in the value of its telecoms offshoot Energis in the past year and is suffering losses from ventures in South America.
Lattice, without a chief executive for several months, recently accepted a tight price regime from British regulator Ofgem that some analysts have said threatens future dividend growth.
The deal will end a 12-year period since British power sector privatisation in which foreign firms have dominated major utility takeovers in Britain.
It could also produce the "national champion" critics have called for to rival the European giants such as Electricite de France, RWE and E.ON who are expanding into deregulating markets - including Britain.