Vodafone has sold its 45% stake in Verizon Wireless to the American telecoms group Verizon Communications in one of the biggest deals in corporate history.
The £84 billion deal was announced by Vodafone after the close of trading on the London Stock Exchange.
The company will return £54bn to its shareholders, of which £22 bn will go to shareholders in Britain.
Despite the size of the deal, it will not generate any tax revenue for the UK.
Vodafone will also invest money in its business, with funds earmarked for high speed mobile phone networks.
It said that by 2017 its main five European markets would have almost complete 4G coverage.
Vodafone chief executive Vittorio Colao told BBC News: "We got an offer that we thought was in the interests of our shareholders to accept - at the end of the day it's as simple as that."
The company is launching a £6bn investment plan called Project Spring, which will accelerate the introduction of 4G networks and increase investment in laying fibre optic cables, among other things.
The investments would allow the company to offer much faster broadband services to customers.
Project Spring will also add to Vodafone's high street stores and develop mobile payment services.
Analysts said that the funds would also allow Vodafone to invest in Europe.
"I think Vodafone has looked at its European market and decided it needs to consolidate its business in a number of countries by buying up broadband and cable TV assets to go with its mobile businesses," said Mark Newman, telecoms analyst at consultancy Informa.
It is the third biggest corporate transaction, behind Vodafone's 1999 deal to buy Germany's Mannesmann and AOL's purchase of Time Warner in 2000.