Four-in-10 disabled children 'in poverty'
Four in 10 disabled children in the UK live "in poverty", according to the Children's Society.
In the population as a whole, about one-in-three children lives in poverty.
The charity is calling on the government to rethink planned changes to welfare benefits in the UK, saying more than 100,000 disabled children could lose up to £27 a week.
The government says the most severely disabled children will receive more money under the changes.
Its Welfare Reform Bill is nearing its final stage in parliament before it becomes law.
From 2013, it will bring in a single monthly payment - known as a Universal Credit - which will replace a range of benefits.
The Children's Society says a new study it has carried out shows 320,000 disabled children in the UK live in poverty.
That is defined as being in a family where the income is less than 60% of the national average.
The charity says nearly a third of the 320,000 live in "severe poverty" - where the income is less than 40% of the average.
It says the welfare changes could mean more families with disabled children fall below the poverty line.
At the moment, families with a disabled child may currently be entitled to support through the disability elements of child tax credit.
Under plans set out for Universal Credit, this support will be given through what is is called "disability additions", within household benefit entitlements.
The government plans to halve the maximum level of support provided through the disability additions - from £54 per week, down to £27 per week.
But it says the plans will mean more financial support for the most severely disabled children.
Bob Reitemeier, chief executive of the Children's Society, said: "These findings are staggering and very worrying. Hidden costs, such as transport, heating and learning aids are forcing more disabled children and young people and their families into poverty.
"It is essential that the government does not cut rates of support for disabled children under the Universal Credit. We believe that this cut in support can only lead to more disabled children being pushed into poverty and we are urging the government to review it."
The charity is one of 30 which have launched a petition called "Don't let disabled children pay the price of welfare reform", which has attracted 5,000 signatures.
A spokesman for the Department for Work and Pensions said: "The government will continue to spend over £40bn on supporting disabled people. The changes we will introduce through Universal Credit will mean that severely disabled children will receive more support than they presently do under existing rules.
"Under Universal Credit there will be no cash losers for existing claimants where their circumstances remain the same."
"We want to... ensure that people receive the same level of support from childhood and beyond, with resources targeted at those people who need the most help.
"Over the last decade vast sums of money have been poured into the benefits system in an attempt to address poverty - this approach has failed. Our radical welfare reforms will benefit the poorest in society and target support at those who need it most to make work pay and break the benefits trap."
The shake-up of the welfare system is a key element of government changes - and one which ministers say will simplify the system and help cut the billions of pounds wrongly paid out through fraud and error.
Universal Credit is also intended to encourage claimants to work, by allowing them to keep more of their benefits when they start to earn.