Labour and the SNP have both accused David Cameron's Government of failing to deliver the Smith Commission proposals on extra welfare powers.

Amid a furious row, one SNP MP accused Scottish Secretary David Mundell of acting like a "colossal governor-general" presiding over the Scottish people with "no shame".

Conservative employment minister Priti Patel rejected the claims saying the Scotland Bill going through Westminster implemented the cross-party recommendations in full, including on welfare.

The Bill handed "extensive new powers" to the Scottish Government, she told MPs as they debated the measures.

The row is not the first time there has been disagreement over how to deliver the welfare component of the Smith agreement.

Before the General Election the Chancellor George Osborne told MPs creating a second "top-up pension" in Scotland would "go against the spirit" of the deal.

However, his Lib Dem deputy Danny Alexander said that Holyrood would have that power.

Yesterday, both Labour and the SNP tabled a number of amendments to Scotland Bill related to welfare.

These would have allowed the Scottish Parliament to mitigate Conservative cuts to tax credits or other benefits.

The proposals were designed to allow MSPs to create new benefits and top up existing payments.

Both Labour and the SNP said the issue was critical because of the Conservative Government's pledge to slash an extra £12 billion from the welfare bill.

Critics warn the move will hurt the most vulnerable in society, while the Tories insist it will help free many from a lifetime on benefits.

Scottish Secretary David Mundell has also challenged the SNP to "come clean" on how much its welfare plans would cost workers.

Shadow Scottish secretary Ian Murray said the amendments would have effectively allowed Holyrood to design its own welfare system.

He said that his party's proposals would have implemented the Smith recommendations both in spirit and in substance.

In n an attack on the SNP, however, he told MPs only Labour's push would ensue the welfare state remained UK-wide.

"Unlike others we are determined to ensure the welfare state remains an integrated UK-wide system of social security to allow for the continued pooling and sharing of risks and pooling and sharing of resources," he said.

Dr Eilidh Whiteford, SNP Westminster spokesman on social justice, said her party's amendments would have improved the system.

She hit out at benefits sanctions saying: "Members in this House who can turn up five minutes late to meetings all over this place don't lose their pay because of that.

"So why should the most vulnerable, the disabled people in our communities ?"

She added that Scotland "could do so much better".

North Ayrshire and Arran SNP MP Patricia Gibson accused Scottish Secretary David Mundell of being a "colossal governor-general" who presided over the Scottish people with "no shame".

Tory MP Julian Knight accused both parties of trying to "turn back the clock" on benefit reform, ans allowing a return to "rampant welfare-ism".

But another Conservative MP Sir Edward Leigh, proposed a clause which would hand Holyrood all social security schemes, including national insurance and housing benefit, as well as child support, occupational and personal pensions and war pensions.

He said that by transferring certain powers, "we are giving, I think, the SNP a crowbar to blast the union apart".

"Just enough purchase on that crowbar, just enough powers given away by this Parliament to feed a sense of grievance. I think if we were to give the Scottish Parliament full responsibility for social security it would be very difficult for them to feed on that grievance, they would have to be a responsible parliament taking responsible decisions and I am confident that they would do so."

The amendments were defeated.