National Grid Transco has bought a network of mobile phone masts and broadcasting towers across Britain for £1.1 billion.
The group, which owns Britain's electricity and gas network, said the acquisition of the UK business of Crown Castle International would bring annual savings of £18m.
The purchase adds 3,500 mobile sites and 750 television towers to National Grid's own portfolio, which features 1,400 sites.
National Grid said the merged company would benefit from growth in the mobile and broadcast infrastructure markets, with Crown Castle 'particularly well positioned' for the move towards digital television.
The enlarged business will initially trade as Crown Castle UK, although this will be reviewed later.
Crown Castle, which bought the TV and radio towers business of the BBC in 1997, posted adjusted earnings before interest, tax, depreciation and goodwill of £101m last year, on revenues of £233m
