An STV investigation has uncovered that the level of school clothing grant issued by local councils varies by as much as £70 around the country.
Freedom of Information responses from 30 local authorities in Scotland show that parents on low incomes can be given anything between £40 and £110 to pay for school uniforms each year.
The Education Act stipulates that local authorities must make provision for the clothing of pupils who would otherwise be unable to afford schoolwear.
Among the responses were North Ayrshire Council, who pay £40, and West Lothian who issue £110 per secondary school pupil eligible for the grant.
Charities, who have been lobbying for government action on school clothing grants for six years, have called for guidance to ensure that a minimum level of grant is set at £70, that eligibility criteria should be widened and that costlier items depicting school logos be reviewed.
John Dickie of the Child Poverty Action Group Scotland said: “We’ve had a longstanding concern about how the costs families face at school can have an impact on the family budget.
“It’s about what impact it can have in terms of excluding children and making it difficult to get the most out of the school day.
“School clothing grants play an important role. They are an important source of financial support for families.
“We’ve become increasingly aware that there was this postcode lottery and inconsistency across Scotland in terms of how much support was available to families in terms of the value and who was entitled.
“The idea of establishing some kind of consistency is important.
“It’s really important that authorities are thinking through what the actual costs are in their area and reviewing the school clothing grant in light of what those actual costs are.
“Its time for them to act on reasonable and modest recommendations.”
Data compiled by STV also shows that many councils have not increased the level of grant for at least ten years.
However, Orkney, Aberdeen, Renfewshire, West Lothian, North Lanarkshire, Inverclyde and Dumfries and Galloway have all improved their provision, whilst North Ayrshire cut their grant from £50 to £40 last year.
Lisa Gillen, a mother of three from Oatlands in Glasgow, said: “By the time you’ve bought shoes, a bag, a jacket, two skirts, two jumpers and two shirts, the £47 grant you get in Glasgow is no where near enough.
“It is taken up with shoes and a bag and a jacket.
“You can go out and buy cheap clothes but the cheaper clothes don’t last very long so you’d have to go and buy other stuff anyway.”
The Scottish Government set up a group to review school clothing grant provision in 2006, which involved charities and government officers.
A report was published in 2011 which recommended that the government issue guidance to local authorities on eligibility criteria, a minimum level be set across the country and that councils regularly review the amount the offer.
A spokesman for the Scottish Government said: "The Scottish Government is committed to tackling child poverty. When the working group's report was published we welcomed its recommendations.
"Local authorities are obliged to provide free school meals as required and also to help parents who are unable to provide adequate school clothing for their children, often through school clothing grants or vouchers."
A spokesman for North Ayrshire Council said: “The level of School Clothing Grant is established to support as many parents and families across North Ayrshire as possible.
"As well as grants, we also provide advice to ensure that they get all of the support and benefits they are entitled to - including income support, tax credits, housing benefit and council tax benefit."
Councils in Moray and East Lothian are still to collate their information. This data will be updated when it is provided.