Labour's manifesto will offer a vision of a Britain in which "nobody is ignored, nobody is forgotten, nobody is left behind", Jeremy Corbyn has said.
Mr Corbyn was speaking after a meeting of the party's shadow cabinet and national executive committee unanimously approved the document, believed to set out plans to nationalise key industries and reverse years of austerity.
Labour's launch plans were thrown into disarray by the leak of a draft version of the document to national newspapers.
Prime Minister Theresa May said the leaked draft suggested Labour wanted to take Britain "back to the past".
Mr Corbyn predicted the policies would prove "very popular" and said they amounted to "an offer that will transform the lives of many people in our society and ensure that we have a government in Britain on June 8 that will work for the many, not the few, and give everyone in our society a decent opportunity and a decent chance, so nobody is ignored, nobody is forgotten and nobody is left behind."
According to the leaked document obtained by the Daily Mirror and Telegraph, a Corbyn government would:
:: Renationalise railways as each private franchise expires, with fares frozen and guards put back on driver-only trains.
:: Establish publicly-owned bus companies.
:: Return Royal Mail to public ownership following the coalition government's "historic mistake" of selling it off.
:: Take energy "back into public ownership" by setting up a rival to the existing Big Six private firms.
To pay for the policy pledges, Labour has already announced plans to hike corporation tax to 26% by 2022, bringing in an extra £20 billion for the Exchequer, and indicated people earning more than £80,000 will face tax rises.
The manifesto indicates a further levy on firms "with high numbers of staff on very high pay".
In an effort to bridge party divides over Trident, it commits Labour to the nuclear deterrent, but in a nod to Mr Corbyn's opposition to the weapons it says "any prime minister should be extremely cautious about ordering the use of weapons of mass destruction which would result in the indiscriminate killing of millions of innocent civilians".
Despite Mr Corbyn's declaration that the Brexit question was "settled" by last year's referendum, the document states withdrawing from the EU without a deal would be the "worst possible" outcome and would be rejected as a "viable" option.
The document also declines to set a numerical target for net migration.
Mr Corbyn vowed the final manifesto would include "costings of all the pledges and promises that we make".
He said the draft was the result of "the most informed, interesting, sensible discussion and debate" within the party and had been amended at Thursday's meeting, attended by senior figures from Labour and trade unions.
It is due for its formal publication next week.
One party insider told the Press Association the leaked draft was an earlier version which had been subject to rewriting in at least one section before the gathering.
The Labour leader pulled out of a planned campaign event as the party fought to contain the damage from the extraordinary leak.
Disarray surrounding the security breach was heightened when a BBC cameraman was injured by a car carrying Mr Corbyn to the meeting.
Tories branded the manifesto a recipe for taxes and borrowing which would put the UK on the "road to ruin".
Mrs May told Channel 4 News the "shambolic" way the document emerged "shows the sort of chaos that we would see from a Labour government".
She added: "If you take their manifesto overall, actually, what they are suggesting is taking us back to the past.
"What I'm interested in is dealing with the challenges that we face today but making a better future for this country."
Leaving the meeting, Unite union boss Len McCluskey said the manifesto was "brilliant" and claimed there was "complete unanimity" among those present about its contents.
Shadow chancellor John McDonnell insisted it was "a modernising, exciting new modern manifesto".
Liberal Democrat leader Tim Farron told the Press Association: "It doesn't matter whether it was leaked or not leaked, the Labour manifesto ceased to be relevant in any way, shape or form the moment Jeremy Corbyn and his party held hands with Ukip and Theresa May and voted for the triggering of Article 50."
Former Scottish National Party leader Alex Salmond accused Labour of becoming a "magpie party", as the draft manifesto featured policies pioneered by the SNP including free university tuition, an end to hospital parking charges and abolishing the "bedroom tax".