A Labour government would give British people the chance to "take our wealth back" from tax cheats, rip-off bosses and greedy bankers, Jeremy Corbyn has promised.

Launching Labour's official General Election campaign in Manchester, Mr Corbyn warned there will be "a reckoning" if he wins power in the June 8 poll and breaks up a system rigged in favour of the wealthy and against ordinary workers.

The Labour leader sought to neutralise the Brexit issue which Theresa May and Tim Farron have put at the heart of their campaigns, insisting that there is no going back from last year's decision for the UK to leave the EU.

"This election isn't about Brexit itself," he said. "That issue has been settled. The question now is what sort of Brexit do we want - and what sort of country do we want Britain to be after Brexit?

"Labour wants a jobs-first Brexit. A Brexit that safeguards the future of Britain's vital industries, a Brexit that paves the way to a genuinely fairer society, protecting human rights, and an upgraded economy."

Mr Corbyn was joined on stage by Andy Burnham, who last week missed a photocall with the leader on the evening of his election as metro mayor of Greater Manchester in one of the few points of light in Labour's gloomy local elections.

And he was introduced by Coronation Street and Broadchurch actress Julie Hesmondhalgh, who told cheering activists that they had a month to ensure that a Labour victory turned the UK into "a society that truly gives a toss about stuff".

Mr Corbyn said that in the coming days Labour would be spelling out the details of a "plan for Britain" to transform the country and change an economy which was "still rigged in favour of the rich and powerful".

"Today, I say to tax cheats, the rip-off bosses, the greedy bankers; enough is enough," he declared.

"In this election, Labour is standing for decent jobs, investment for the future, shared wealth creation, security at work, affordable homes for all, a fully funded NHS and schools, training and skills, an end to rip-off privatisation, fair taxation and a fairer, more equal country.

"As we set out our detailed plans for Britain, the scale of the change we are offering will become clear.

"So let's turn our country around. Let's come together to transform Britain. Together, we can win for the many not the few."

He urged supporters: "Don't wake up on June 9 to see celebrations from the tax cheats, the press barons, the greedy bankers, Philip Green, the Southern Rail directors and crooked financiers that take our wealth, who have got away with it because the party they own, the Conservative Party, has won.

"We have four weeks to ruin their party. We have four weeks to have a chance to take our wealth back."

Mr Corbyn noted the Sunday Times Rich List last weekend found the 1,000 best-off people in the country had seen their wealth grow by 14% in the last year.

"Imagine the outcry if public sector workers put in for a 14% pay rise," he said.

"But it's no surprise that the richest have got even richer after the tens of billions the Tories have handed them in tax cuts."

Mr Corbyn acknowledged Labour faced a "big... challenge" following last week's local elections, which saw the party shed more than 380 councillors.

He accepted many voters were "sceptical and undecided ... not sure which way to turn", adding: "Who can blame them? People are alienated from politics and politicians.

"Our Westminster system is broken and our economy is rigged. Both are run in the interests of the few."

He said he expected "hostility" for challenging the vested interests that benefit from the system, but urged voters not to "resign themselves to things the way they are, underestimating just how many more burdens the Tories could impose if their mission to rig the system for the rich isn't halted".

Mr Corbyn accused Mrs May of putting party interests ahead of the national interest by claiming the election was "all about Brexit and who can play at being toughest with Brussels".

He derided her promises to build a fairer Britain, insisting she was implicated in the Conservative-led government's record of cutting disabled people's benefits, increasing tuition fees and creating the so-called "bedroom tax".

Labour would "upgrade the economy" with new infrastucture and investment in training and skills, as well as "rebuilding" the NHS and social care, building a million homes, strengthening workplace rights and tackling the "scandal" of air pollution, he said.

Liberal Democrat Leader Tim Farron, who has promised a second referendum on any Brexit deal, said: "Corbyn's claim that Brexit is 'settled' is further proof of his inability to stand up to the Tories on the most important issue facing our country.

"He made his party vote in Parliament with the Conservatives on Brexit, and now he is joining Theresa May in denying the British people a final say on the deal."

Meantime, Mr Corbyn will take to the streets in a red bus emblazoned with his message Labour is "for the many not the few" as he seeks to persuade voters to back him in the General Election.

The slogan on the "executive" vehicle is likely to prove far less controversial than the now-infamous claim on the Vote Leave campaign bus, that Britain sends £350 million a week to the EU that could be spent on the NHS, during last year's referendum.

The coach has been modified for the slog of the campaign, with seats taken out to make room for tables for all-important strategy meetings, and, as the campaign revs up, probably Mr Corbyn's meals.

Labour has decided not to tail the 10-metre long, 3.8m high, 2.5m wide leader's coach with the traditional media bus, but it does not appear to have dented interest in the campaign.