The UK government’s attempt to make legislative changes to the definition of child poverty will not be replicated in Scotland as they would exclude working poor households, social justice secretary Alex Neil has told Westminster.

In a letter to the secretary of state for work and pensions, the cabinet secretary outlined the Scottish Government’s opposition to proposals in the Welfare Reform and Work Bill. The changes mean the UK government will no longer be bound by statutory targets to reduce the number of children in poverty and will instead focus on ‘worklessness’ and ‘educational attainment’ – ignoring the significant problem of in-work poverty.

In addition, the Social Mobility and Child Poverty Commission will have its remit narrowed and be called the Social Mobility Commission.

Mr Neil has requested the UK government repeal all parts of the Child Poverty Act 2010 relevant to Scotland, and confirmed the Scottish Government will remove itself from the new Social Mobility Commission, which has previously monitored and reported on the progress of governments in tackling child poverty.

He announced the Scottish Government will now work with stakeholders and the independent poverty advisor to build on the sophisticated measurement framework already in place in Scotland. This engagement will help develop a distinct and Scottish approach which does not ignore the increasing problem of in-work poverty which affects 120,000 children after housing costs.

The letter comes ahead of the UK Parliament’s first committee meeting to discuss the Welfare Reform and Work Bill on Thursday.

He said: “The Scottish Government refuses to cut loose the 120,000 children whose parents are working on low incomes and struggling to pay their bills. We want to tackle child poverty not sweep it under the carpet.

“UK government proposals to change the definition of child poverty will only hide the problem and will do nothing to address it.

“If the UK government insists on taking this approach then they must repeal Scottish elements of the Bill as the Scottish Government cannot abide by legislation that fails to show the reality of poverty and ignores the working poor.

“As a result of this the Scottish Government will not be part of the new Social Mobility Commission but we will continue to co-operate with them in the future.

“Scotland already has in place an innovative and widely supported measurement framework which addresses the impacts poverty has on the lives of children and their families. We will now begin discussions with stakeholders and our independent poverty adviser on further developing a Scottish approach to tackling, measuring, and reporting on poverty as well as the targets and action being taken to reduce poverty.

“Developing our own approach will help us to find the most effective ways to address poverty and inequalities and continue our priority of creating a fairer and more equal society.”

John Dickie, director of Child Poverty Action Group in Scotland, said: “The UK government’s abandonment of child poverty is a devastating blow to efforts to ensure all our children grow up in families with the resources to give their children the best possible start in life and it is now vital that the Scottish Government’s child poverty strategy and ambitions are put on a statutory footing to protect and sustain the progress that has already been made.”

Satwat Rehman, director of One Parent Families Scotland (OPFS) and a member of the Child Poverty Ministerial Advisory Group said: “Changes to the poverty measure used by the UK Government indicates it is moving the goalposts - scrapping legally binding targets it is not on course to meet, rather than implementing policies that would tackle the real causes of poverty.

“The most recent statistics showed that absolute child poverty has risen by half a million since 2010 and that progress on relative poverty has stalled. Two thirds of poor children are in working families – but these children would not be counted as poor in the future. A child poverty strategy which excludes income isn’t a child poverty strategy.

“OPFS looks forward to working with other anti-poverty charities in Scotland to build on the Scottish Government’s existing measurement framework to develop a robust, evidence based approach to tackling child poverty underpinned by clear statutory targets and duties.

“This must tackle the real root causes, and address the fact that low benefit levels inflict poverty on families and that the majority of children growing up poor in Scotland are living in families where parents are working, but not earning enough to pay the bills. Finally, it must measure the thing we all know makes the difference – how much money families have to live on.”