Inequality in Britain has continued to increase since Labour came to power, an influential think tank has said.
The IPPR says some poor have not received enough help
The Institute for Public Policy Research (IPPR) says there have been improvements since it published a major report on social justice a decade ago.
Fewer people are living in poverty than in 1997, but the proportion of wealth held by Britain's richest 10% rose from 47% to 54% during the 1990s, it said.
It has called on Labour to "publicly advocate a fairer, more equal Britain".
When the IPPR released its report 10 years ago, Tony Blair said it would "inform" his policies.
In its latest report, it praises the government for cutting child poverty, which ministers have pledged to eliminate by 2020.
But it says other groups of poor people have not received enough help.
It points out that the proportion of childless adults living in poverty has gone up in the last 10 years, as well as the wealth inequalities increasing.
IPPR director Nick Pearce said his report underlined how much still needed to be done and that the next five years would be "critical".
"We would expect it to take longer for Labour to tackle things like wealth inequality than poverty but it does show how far we have to go and the challenges we have got before us," he told BBC Radio 4's Today Programme.
"Despite the boldness of its pledge to eradicate child poverty and the expansion of investment in public services, the government does not consistently articulate and publicly advocate a fairer, more equal Britain," he said.
"To achieve firm foundations for a 'progressive century', the government needs to lead public debate more firmly in a progressive direction - to explain, justify and secure support for social justice."
Some IPPR Findings
Wealth held by the top 10% has increased 7% to 54%
Fewer living in poverty than in 1997
Women more likely to live in poverty
People's lives largely determined by parents' social class and skin colour
Low voter turnout giving wealthier more political influence
His comments were reflected by former Transport and General Workers Union general secretary Sir Bill Morris.
The fact that the top 10% had got richer showed there was a need for a "radical agenda", he said.
"We should have a clearly declared intention to close the gap through radical social reform," he told Today.
Policies like investing the proceeds of the windfall tax on the privatised utilities into the New Deal had led to the elimination of youth unemployment, he said.
Economic secretary to the Treasury John Healey pointed out that families from the poorest fifth of the population were £3,000 a year better off than in 1997.
There were also 1.5m fewer children in low-income households, he said.
"There's been a lot of good done and there's a lot to do," he told Today.
But "wealth inequality" was a "very deep-seated" inequality which took longer to tackle, he said.
"It's hardly achievable in the short term that's why we have got a long programme for the future. It's a long term generational political challenge," he added.
BBC political correspondent Shaun Leys says the IPPR report is potentially embarrassing because it comes from a Labour Party sympathiser.
There may be more criticism to come as the institute plans to update its 1994 report in full, in an attempt to influence Labour's manifesto for the next general election, he said.