The scale of Britain's growing inequality is revealed today by a report from a leading charity showing that the country's five richest families now own more wealth than the poorest 20% of the population.

Oxfam urged the chancellor George Osborne to use Wednesday's budget to make a fresh assault on tax avoidance and introduce a living wage in a report highlighting how a handful of the super-rich, headed by the Duke of Westminster, have more money and financial assets than 12.6 million Britons put together.

The development charity, which has opened UK programmes to tackle poverty, said the government should explore the possibility of a wealth tax after revealing how income gains and the benefits of rising asset prices had disproportionately helped those at the top.

Although Labour is seeking to make living standards central to the political debate in the run-up to next year's general election, Osborne is determined not to abandon the deficit-reduction strategy that has been in place since 2010. But he is likely to announce a fresh crackdown on tax avoidance and measures aimed at overseas owners of high-value London property in order to pay for modest tax cuts for working families.

The early stages of the UK's most severe post-war recession saw a fall in inequality as the least well-off were shielded by tax credits and benefits. But the trend has been reversed in recent years as a result of falling real wages, the rising cost of food and fuel, and by the exclusion of most poor families from home and share ownership.

In a report, a Tale of Two Britains, Oxfam said the poorest 20% in the UK had wealth totalling £28.1bn – an average of £2,230 each. The latest rich list from Forbes magazine showed that the five top UK entries – the family of the Duke of Westminster, David and Simon Reuben, the Hinduja brothers, the Cadogan family, and Sports Direct retail boss Mike Ashley – between them had property, savings and other assets worth £28.2bn.

The most affluent family in Britain, headed by Major General Gerald Grosvenor, owns 77 hectares (190 acres) of prime real estate in Belgravia, London, and has been a beneficiary of the foreign money flooding in to the capital's soaring property market in recent years. Oxfam said Grosvenor and his family had more wealth (£7.9bn) than the poorest 10% of the UK population (£7.8bn).

Oxfam's director of campaigns and policy, Ben 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.

READ MORE: Britain's five richest families worth more than poorest 20%

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