Almost half of children in one parliamentary constituency live in poverty, according to a study comparing wealth levels across the UK.
The data, collated last year, suggests that 47% of children in Manchester Central live in households earning less than 60% of median income.
In Sheffield Hallam, fewer than 5% of children were in such households.
Enver Soloman, chairman of the End Child Poverty campaign, said the study found "gross levels of inequality".
The figures are based on data collated by researchers for the campaign group, which is itself made up of more than 100 charities. The figures are broken down by parliamentary constituency, local authority and council ward.
The researchers used local tax credit data and regional trends in worklessness to estimate the number of low income families in each area.
The researchers explain that these are estimates so are not directly comparable with the most recent official figures for child poverty, which was reported in figures published last June to have stood at 18% in 2010/11.
The End Child Poverty estimate - based on its analysis of the data it had available - came out at 20.2% nationwide, but it said that its study would aim to show the huge variation in different areas.
It even says that there are huge differences within some regions, pointing out that in north west England, a 38% poverty level among children living in Manchester can be contrasted with a figure of 7% in Ribble Valley.
In London the figure for Bethnal Green and Bow is 42% but only 6% in Wimbledon.
The figures suggest that in some 69 council wards - areas which are much smaller in size and population than parliamentary constituencies - more than half of children are in poverty.
In terms of local authorities, Tower Hamlets in London had the highest levels of child poverty, with 42% of children growing up in poverty.
The report says that being poor damages childhood and harms children's future prospects. It draws on earlier research from Save the Children which detailed the effects of poverty on UK children's wellbeing, with parents cutting back on food (61%), skipping meals (26%), not replacing children's outgrown shoes (19%) and winter coats (14%), missing school trips (19%) and having to borrow to make ends meet (80%).
"Far too many children whose parents are struggling to make a living are having to go hungry and miss out on the essentials of a decent childhood that all young people should be entitled to," said Mr Solomon.
"The government must also closely examine its current strategy for reducing poverty and consider what more it could do to ensure millions of children's lives are not blighted by the corrosive impact that poverty has on their daily existence.''
He also called on local authorities "to prioritise low income families in the decisions they make about local welfare spending".
The campaign has written to local authorities with the most child poverty asking them what they plan to do about tackling child poverty locally.
A spokeswoman for the Department of Work and Pensions said the government remained committed to eradicating child poverty by tackling its root causes and with welfare reforms aimed at improving the lives of some of the poorest families.