"We'll tax the giant corporations fairly - the Facebooks and the Googles - to cover the running costs", said Corbyn, adding the public had been forced to pay far too much for "rip-off broadband" and the party would transform the British economy.
"It's time to make the very fastest full-fibre broadband free to everybody, in every home in every corner of the country", Labour leader Jeremy Corbyn will say in a speech, according to an extract released by the party.
Britain's opposition Labour Party said it would nationalise parts of telecoms provider BT's network if it won power in the December 12 election to provide free full-fibre broadband for all.
Meanwhile, the cost of bringing parts of BT into public ownership will be set by Parliament and paid for by swapping bonds for shares.
The Labour leader said his party was determined to end the "horror" of spending cuts which began when the Lib Dems were in coalition with the Conservatives.
The relatively muted share price response was likely to be, said Russ Mould at AJ Bell, a reflection of "investors' scepticism about the plan getting off the ground".
In what would amount to the biggest shake-up in British telecoms since Thatcher's privatizations of the 1980s, Labour said few would lose out while millions would benefit.
"We also have hundreds of thousands of people who used to work for BT who have pensions that they rely on, and we've got to make sure we're generating the returns for those pensioners, and also very, very importantly, for our shareholders, because ultimately they now own the company". Its only competitor with widespread coverage is Virgin Media, owned by Liberty Global. It's also unclear what, if any compensation would be made available, and if jobs lost as a result of the plan would be covered by Labour's employment pledge.
TalkTalk said on Friday a deal to sell its FibreNation business had stalled after Labour's announcement.
"We'll come to an agreement with them".
Twenty-four top British writers, actors, activists, businesspeople, tech entrepreneurs and others have signed an open letter urging voters to not back the Jeremy Corbyn-led Labour party in next month's parliamentary elections due to the antisemitism scandals it has been plagued by in recent years.
"These are very, very ambitious ideas and the Conservative Party have their own ambitious idea for full fiber for everyone by 2025 and how we do it is not straightforward", Chief Executive Philip Jansen told the BBC.
Full-fibre is a newer, faster broadband technology which relies on fibre-optic cables, instead of the old copper cabling, entirely.
They said there would be a one-off capital cost to roll out the full-fibre network of £15.3 billion, in addition to the Government's existing and not yet spent £5 billion commitment.
In a speech on Friday, Mr Corbyn will say the internet has become such a central part of our lives, adding: "That's why full-fibre broadband must be a public service, bringing communities together, with equal access, in an inclusive and connected society".
The Communication Workers Union said Labour's plan would create "thousands of good jobs across the UK".
The Conservatives said the real cost would be over 83 billion pounds over a decade.