DAVID Mundell, the new Scottish Secretary, is facing intense pressure to strengthen the UK Government's new Scotland Bill before it is published next week.

Scottish Government ministers and backbench MSPs from across the political divide have sent a powerful message that legislation transferring new powers to Holyrood must match recommendations made by the Smith Commission.

John Swinney, the Deputy First Minister, claimed the UK Government was preparing a watered down bill with the intention of making cosmetic changes at a later date.

He said, under such circumstances, the government should not be allowed to claim credit for making "concessions".

His warning, in a briefing for cabinet colleagues, came as backbench MSPs met Mr Mundell at the Scotland Office in London.

Bruce Crawford, the convener of the devolution committee, said the delegation was given assurances that some amendments would be made to draft legislative clauses published last year but said the group would like to see "more change" before the Bill is published.

Mr Mundell insisted the Bill would reflect the Smith Commission recommendations, which were agreed by Holyrood's five parties after last year's independence referendum.

The incoming Conservative Government has backed an extensive programme of devolution, based on the Smith deal, including handing Holyrood almost full control over income tax, new borrowing powers and responsibility for disability benefits.

However, a report by MSPs last week has sparked a stand off between Holyrood and the UK Government.

The Scottish Parliament's devolution committee said draft legislation stopped short of the full Smith proposals.

In particular, the committee raised concerns that the draft legislation would not allow the Scottish Government to create new benefits, would give UK ministers a veto over welfare changes, and could create confusion over who paid income tax in Scotland.

A Bill based in the draft legislation will be presented to MPs within months.

It topped the agenda at Nicola Sturgeon's cabinet meeting in Edinburgh yesterday, when Mr Swinney warned the Bill must live up to the "spirit and substance" of the Smith agreement.

The First Minister's spokesman said: "We want the Bill as introduced to fully reflect Smith.

"If the Scotland Bill only ends up reflecting Smith after amendments are accepted, that cannot be portrayed as a major concession by the UK Government.

"It is what everyone signed up to in the first place."

As it goes through parliament, the SNP will seek to amend the Bill to include what it calls "priority devolution" - handing Holyrood control over National Insurance Contributions, employment law including the minimum wage and further responsibility for welfare.

Mr Mundell met Mr Crawford, Linda Fabiani, one of the SNP negotiators during the Smith Commission talks, and Labour's Lewis Macdonald.

Speaking afterwards, Mr Crawford said he would "reserve judgement" until he saw the Scotland Bill as to whether or not the UK Government had satisfied the committee's suggested improvements on meeting the recommendations of the Smith Commission on more powers. The Bill is due to be published next Thursday, the day after the Queen's Speech.

Mr Crawford also stressed that it was "absolutely fundamental" that the two governments worked out the fiscal framework on how the proposed new tax powers for Holyrood would work and that this was "in place" before the Bill could be passed and before the Scottish Parliament could give its approval through a so-called legislative consent motion. Intensive meetings between the two governments were already underway on this, he explained.

He said the meeting with Mr Mundell was constructive and helpful, adding: "Our job was to make sure that the baseline of Smith was achieved.

"As we said when we published our report, we did not think in either the spirit or the substance that that baseline had been achieved.

"I hope we have got closer to getting that today but I will need to see the Bill when it is published shortly after the Queen's Speech to make a judgement about it."

Mundell said: "I have made my position clear: the UK Government will deliver the Smith recommendations, giving Scotland one of the most powerful devolved parliaments in the world.

"It will have powers over a wide range of tax decisions, including the Scottish rate of income tax, as well as additional powers in many other areas.

"This strikes the perfect balance of a strong Scotland within the security of the wider UK."

The new Scotland Bill will be in the first clutch of legislation published next Thursday. The Conservative Government intends to begin its parliamentary process soon with the detailed scrutiny stage, the Committee Stage, beginning in July. The plan is to have it on the Statute Book by early 2016, ahead of next May's Holyrood elections.