A senior Labour Party figure has called on Nicola Sturgeon to use Holyrood's new powers to revive a key part of her anti-poverty legislation that was scrapped by the Conservatives.

Harriet Harman, who was interim leader before Jeremy Corbyn's election, urged the First Minister to back a recommendation from her own poverty tsar and implement the "socio-economic duty," part of the groundbreaking Equalities Act.

The duty was designed to make ministers assess their policies in terms of the benefit they bring to the poor.

It was ditched by Theresa May when she became Home Secretary in 2010 before it was ever implemented.

Ms Harman, who introduced the equalities legislation as one of the final acts of the last Labour government, said Ms Sturgeon should revive it in Scotland using powers due to be devolved under the new Scotland Bill.

The First Minister's adviser on poverty, Naomi Eisenstadt, recommended the move in a report last week.

Ms Harman said: "The Scottish Government should definitely implement this as soon as they have the powers.

"If the they have the opportunity to do it, why on Earth not do it right away?

"It makes ministers look at every single policy and ask, will this narrow the gap between rich and poor.

"It is not just about poverty, it's about equality.

"The Coalition refused to implement it but it would be great if were it implemented in Scotland."

Johann Lamont, the former Scottish Labour leader, said the move would force ministers to re-open the debate about which services should be provided universally and which targeted at the least well off.

She has faced furious criticism from the SNP in the past for questioning the wisdom of spending billions of pounds freezing council tax bills and providing free prescriptions, free bus travel for the over-60s, free tuition for students and free school meals for all five- to seven-year-olds.

But she said: "I don't expect them to do anything other than slap me down.

"However, their own poverty tsar is saying the same thing.

"There are now serious people in health, education and social care who are all asking whether we have got our priorities right."

She added: "We need to have something like the socio-economic duty to test the full range of policy making against the impact it has on the least well off groups.

"The Scottish Government has never wanted to test its own policies and budget decisions seriously.

"When ministers claim the council tax freeze or free bus passes for the over-60s are about fighting poverty, well, they should test that.

"They need at least to open up this debate instead of shutting it down."

The Equalities Act became law in 2010.

The socio-economic duty only covered England and Wales but Holyrood's equal opportunities committee said it should be adopted in Scotland after a consultation found a majority of public bodies and the Equality and Human Rights Commission were in favour.

The Scottish Government backed the plan and passed a legislative consent motion adopting it.

At the time, Alex Neil, then the Scottish Government's housing and communities minister, told MSPs the Scottish Government was "embracing" the measure.

When Theresa May announced in October 2010 the duty was to be scrapped, Mr Neil wrote to her expressing his disappointment and urging her to reconsider.

Since then the measure has been left in constitutional limbo.

The new Scotland Bill, currently before MPs, will give MSPs explicit powers to resurrect it.

In her report, Ms Eisenstadt said the Scottish Government should use the new powers to implement the social-economic duty, saying it would provide a would "enable a good test on the universal versus targeted debate".

A Scottish Government spokesman said: "Currently we do not have the power to commence the socio-economic duty – it will come to us under the Scotland Act.

"The Scottish Government will consider how to use all new powers that are devolved to the Scottish Parliament to the benefit of the Scottish people."