* Opposition publishes manifesto ahead of Dec. 12 election
* Platform includes shorter working week, sweeping nationalisation
* Labour takes aim at "bankers, billionaires and establishment"
* Leader Corbyn has been criticised over Brexit stance
* Most polls show PM Johnson's Conservatives ahead (Adds economist comment on tax plans)
By Elizabeth Piper and Kylie MacLellan
BIRMINGHAM, England, Nov 21 (Reuters) - Labour leader Jeremy Corbyn unveiled his party's election manifesto on Thursday, setting out radical plans to transform Britain with public sector pay rises, higher taxes on companies and a sweeping nationalisation of infrastructure.
Voters face a stark choice at the country's Dec. 12 election: opposition leader Corbyn's socialist vision, including widespread nationalisation and free public services, or Prime Minister Boris Johnson's drive to deliver Brexit within months and build a "dynamic market economy".
Speaking in Birmingham, Corbyn set out his crowd-pleasing plans, offering something for almost everyone in Britain - from help to parents with young children to free university education and more money for elderly care.
In a speech punctuated by applause and standing ovations from supporters, he promised to stand up for ordinary people against the "bankers, billionaires and the establishment" who were fighting to keep a system "rigged in their favour".
"Labour's manifesto is a manifesto for hope, that is what this document is - a manifesto that will bring real change," Corbyn said, describing his approach as the most "radical and ambitious plan" in decades.
Lagging in the polls, Corbyn hopes his message of change will drown out criticism of his Brexit stance, which even some in his party say lacks the clarity of Johnson's vow to "get Brexit done".
Instead, the Labour leader says he will get Brexit "sorted" in six months, with a new exit deal put to a second referendum as a way to bring the country together.
Hoping to avoid comparisons with Labour's 1983 socialist-inspired manifesto described later by a then Labour lawmaker as "the longest suicide note in history", Corbyn rejected suggestions he was harping back to the 1970s.
He was instead offering "a green industrial revolution", an ambitious plan that, he said, could be paid for in part by taxing the richest in Britain.
The manifesto showed an extra 82.9 billion pounds of spending, matched by 82.9 billion pounds of revenue-raising measures.
"It's impossible to understate just how extraordinary this manifesto is in terms of the sheer scale of money being spent and raised through taxation," said Paul Johnson, Director of the Institute for Fiscal Studies independent think-tank.
He said Labour plans to raise the revenue required from taxes on high earners and corporations were "simply not credible".
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Both parties have promised to end economic austerity and spend more money on public services before the election, which will determine how, when and even whether Britain leaves the European Union.
Brandon Lewis, a Conservative minister, said Labour would go on "a reckless spending spree which would take a sledgehammer to the British economy".
Most pollsters put the Conservatives in front, but few are prepared to predict a victor.
Labour could be in a position to form a minority government if Johnson's Conservatives fall short of outright majority and rivals are prepared to support Corbyn as prime minister.
But to implement its manifesto in full the party would need an even bigger turnaround in the election race to claim a majority of its own. One polling expert described the chances of this as "close to zero" on current evidence.
Held after three years of negotiations to leave the EU, the December election will show how far Brexit has torn traditional political allegiances apart and test an electorate increasingly tired of voting.
Labour has put at the forefront of its campaign its attack on "vested interests", taking aim at Johnson, who was educated at England's elite Eton public school, has considerable personal wealth and whose party has rich backers.
Among the proposals, Labour said it would bring in a windfall tax on oil companies, de-list companies that do not contribute to tackling climate change and increase public sector pay by 5%.
The manifesto also promised to reverse privatisations begun by former Conservative Prime Minister Margaret Thatcher in the 1980s, by nationalising rail, mail, water, and BT's broadband network to provide free internet for all.
Those pledges have been mocked by the Conservatives, with Johnson calling plans to nationalise broadband as a "crazed Communist scheme".
While business groups welcomed investment in infrastructure, they warned many of Labour's policies risked damaging business and the economy.
"Command and control isn't the way," British Chambers of Commerce Director-General Adam Marshall said.
But Corbyn is defiant.
"If the bankers, billionaires and the establishment thought we represented politics as usual, that we could be bought off, that nothing was really going to change - they wouldn't attack us so ferociously," he said. "But they know we mean what we say." (Reporting by Elizabeth Piper; Editing by Lisa Shumaker, Alex Richardson, Guy Faulconbridge and Giles Elgood)