The companies that run the UK's mobile network have agreed a deal to eliminate signal dead zones in remote areas.
The Shared Rural Network aims to extend 4G coverage to 95% of the UK, no matter which network customers use, by 2025, three years later than first planned.
The deal involves sharing network equipment but almost collapsed last month in a row between operators.
Taxpayers will pay half the £1bn cost, which will include new masts. EE, O2, Three and Vodafone will pay the rest.
The government says the plan will "make poor and patchy rural phone coverage a thing of the past".
It should guarantee coverage to an extra 280,000 premises, along 16,000km (10,000 miles) of roads - particularly in so-called "not-spots", where there is no service at all.
The government says Scotland, Wales, and Northern Ireland will see the biggest improvements.
CCS Insight analyst Kester Mann said the deal was a "a rare example of successful collaboration between mobile operators... more often engaged in cut-throat competition".
"It should go a long way to addressing areas of weak coverage in many rural parts of the UK and overcome some of the tough planning and access restrictions that have hindered network rollout in the past," he said.
"It should, therefore, be considered a win-win for both the operators and consumers."
The chief executive of mobile operator Three, Dave Dyson, said the deal was "a game-changer for the country".
Vodafone chief executive Nick Jeffrey said it was "unmatched anywhere in the world".
The deal hit a major stumbling block a month ago, when other operators objected to the proposed cost of using BT-owned EE's equipment.
BT said its costs were fair and based on how much it had invested in its masts and other equipment over the years.
But one source said the proposed charges were so high it would be cheaper for rivals to build their own masts.