That is because for the last seven years our people have lived through the opposite; a Britain run for the rich, the elite and the vested interest.
Addressing the crowd at the event, Mr Lewis said: "Our society is more complex, our social allegiances less fixed, our identities less certain than they were when the Labour Party was born".
The tax hikes will help Labour pay for some of their flagship manifesto promises, including extending 30 hours-a-week of free childcare from working parents of over-twos to all families, which would cost £5bn per year.
Labour will lower the threshold for the 45p rate of income tax from £150,000 to £80,000 and introduce a new 50p rate on earnings over £123,000.
The party is also said to be planning a "fat cat" levy on businesses employing staff on hefty pay packages with a 2.5 per cent rate on those on £330,000, rising to 5 per cent for those on £500,000, according to The Guardian.
A slew of nationalizations in the rail, water and energy industries capped Labour's pitch with Corbyn offering a "radical and responsible" plan to contrast with May's oft-repeated selling point of "strong and stable" leadership.
Even more doubtful is whether jacking up corporation tax would bring in an eyebrow-raising extra £19.4 billion.
Such changes are among the measures to boost the state coffers by the £48.6 billion needed to meet the commitments outlined in the Labour manifesto.
Most of Labour's nationalisation plans were leaked last week, but Corbyn threw water into the mix on Tuesday, pledging to replace the "dysfunctional" water utilities system with a network of regional, publicly owned companies.
It was an emotive occasion in which Jeremy Corbyn was cheered, as he set out a "programme of hope", but a handful of journalists were booed.
Mr Corbyn said Labour was offering "hope" against the "fear" tactics of the Tories.
The Labour leader got the loudest applause from his audience of party activists for his pledges to scrap university tuition fees, guarantee the triple lock for state pensions and build a million new homes.
"I don't think we can reverse it entirely and we shouldn't be promising things we can't afford", she said. "Sensible, costed and when tested, our policies are highly popular with the public", he told AFP.
The governing Conservatives, which have a runaway lead in opinion polls before the election, called the manifesto "a shambles", again attacking veteran peace campaigner, Corbyn.
The manifesto says: "When the 1945 Labour government established the NHS, it created one of the central institutions of fairness of the 20th century". But the message to Conservative lawmakers, members and activists is true to form for the risk-averse prime minister - do not take anything for granted.
David Gauke, Chief Secretary to the Treasury, said Labour's "nonsensical" plans "simply don't add up" and would mean "more borrowing and debt". The Institute of Fiscal Studies said the tax revenue raised was "highly uncertain" and would depend on high earners respond.
On the policy to further crack down on tax havens, ActionAid head of advocacy Charlie Matthews, said, "Stronger anti-tax haven rules could help to tackle corporate tax avoidance in the United Kingdom and around the world, including in some of the world's poorest countries". Labour claim the move will raise £19bn per year.