Ben Philips said the UK government should implement a financial transactions tax to ensure the financial sector “contributes its fair share”.
He called for a focus on the greater taxation of wealth by exploring a land value tax, and set out a long-term strategy to raise the minimum wage to a living wage.
Mr Phillips said: “Austerity policies are massively increasing poverty and inequality in the UK - damage that could take two decades or more to reverse. Our research suggests 800,000 children and an extra 1.9 million adults in the UK could be pushed into poverty by 2020.”
His comments came as Oxfam published a four-page report revealing just five UK households have more money than the poorest 12.6 million Britons put together.
It claimed the five richest families in the UK are wealthier than the bottom 20 per cent of the entire population, while over the past two decades the wealthiest 0.1 per cent have seen their incomes grow nearly four times faster than the least well off 90 per cent of the population.
Mr Phillips said: “Britain is becoming a deeply divided nation with a wealthy elite who are seeing their incomes spiral up, while millions of families are struggling to make ends meet.
“It’s deeply worrying that these extreme levels of wealth inequality exist in Britain today, where just a handful of people have more money than millions struggling to survive on the breadline.”
Chris Daems, director at London-based Principal Financial Solutions, said: “While it is massively important to help families who are struggling to survive, I do not see the benefits in highlighting the difference between the ‘super rich’ and the remainder of the population.
“Instead, we should be focusing our time, effort and energy on stopping shoddy behaviour from people who prey on families who are finding it tough, like doorsteppers and payday lenders. We should also empower people with the knowledge, attitude and skills they need to be able to save, invest and manage their money.”
85 people on the planet own the same amount as half the world’s population
5 families in Britain are wealthier a fifth of the population
0.1 per cent of Britons’ incomes have grown almost four times faster than 90 per cent of the population