Image copyright PA Image caption Ms Sturgeon wants major change to the benefit system delayed

The UK government has rejected a call by Deputy First Minister Nicola Sturgeon to halt the introduction of universal credit in Scotland.

Ms Sturgeon had written to the prime minister asking for a delay while new Scottish devolution powers are considered by Lord Smith's commission.

She argued that introducing universal credit would make it harder to devolve housing benefit to Holyrood.

But a UK government spokesman said its business would continue as planned.

Universal credit is replacing six benefits and tax credits for working-age people with a single payment.

It is being phased in across the UK by 2017 and is already available to some claimants in Inverness.

A cross-party commission led by Lord Smith has been set up to seek agreement on further devolution of powers to Holyrood.

Both Labour and the Conservatives have argued for housing benefit to become a Scottish responsibility.

Analysis

Glenn Campbell, BBC Scotland political correspondent

If there had been a "Yes" vote in the independence referendum, the Scottish government said it would have called on the UK government to halt the implementation of universal credit in Scotland.

This would have allowed SNP ministers to design a Scottish welfare system that retained housing benefit, which is one of six welfare measures being merged into universal credit across the UK.

Despite having lost the referendum, Nicola Sturgeon is calling for the introduction of universal credit to be put on hold in Scotland anyway.

Her argument is that "accelerating" the transition to this new single payment system, as the Work and Pensions Secretary Iain Duncan Smith promised at the Conservative conference on Monday, would compromise plans to devolve control of housing benefit to Holyrood.

Both the Conservatives and a Labour have suggested this measure in their proposals to increase Holyrood's powers, which are now being considered by Lord Smith's commission on further devolution.

Ms Sturgeon says the UK government would not be acting in "good faith" if it pressed on with bringing in universal credit while those talks are underway.

Mr Duncan Smith has said he's determined to finish what he started by introducing universal credit across the UK by 2017.

Ms Sturgeon said: "Iain Duncan Smith said at the Tory conference this week that roll-out of Universal Credit - including in Scotland - is to be 'accelerated'.

"It is hard to see how this is in any way consistent with a good faith approach to the process of agreeing more powers for the Scottish Parliament.

"There is a widespread consensus that the Westminster parties' proposals on the devolution of welfare powers are far too timid and that the Scottish Parliament needs substantial control of the welfare system to help people into work and tackle the growing scandal of poverty in Scotland."

Ms Sturgeon said it was hard to see how even the "limited welfare proposal of the main Westminster parties" - to devolve control of housing benefit - could be delivered if the UK government pressed ahead with Universal Credit.

She added: "Universal Credit effectively abolishes housing benefit. It is not clear to me how we can have a meaningful discussion about devolving a welfare policy that is already in the process of being abolished.

"I have therefore written to the prime minister today asking that the roll-out of Universal Credit - which in any event is already significantly delayed and discredited - is halted in Scotland.

"It is essential that the Westminster parties respect the process of agreeing more powers in actions as well as words."

'Agreed timetable'

Downing Street confirmed it had received Ms Sturgeon's letter, but a UK government spokesman said it did not want to pre-empt the work of Lord Smith's commission.

The spokesman said government business would continue as planned until the commission had reported.

Scottish Labour's welfare spokeswoman Jackie Baillie MSP: "The Smith Commission is rightly looking at devolving a number of powers to the Scottish Parliament, including housing benefit.

"According to the agreed timetable we are expecting a white paper or equivalent document by November and draft clauses published for legislation as the new Scotland Bill by January.

"By then we expect the UK government to take account of cross party agreement and devolve housing benefit to Scotland."