The “waiting period” for those making a Universal Credit claim was introduced by the then chancellor George Osborne in 2013.

Payments for those claiming out-of-work benefits were never paid immediately a claim was made. The rationale for this is that Governments didn’t want to give benefits to people who were not strictly unemployed but on brief gaps between jobs.

But by more than doubling this period, Mr Osborne saved the treasury more than £260m a year.

Read more: Charity says new benefit is harming the poor

That was not the whole story. Universal Credit is paid monthly in arrears, supposedly to mimic or replicate the experience of being in work. Add that into the inevitable bureaucratic delay in processing an application and the minimum delay before a new claimant begins receiving help is six weeks.

According to critics, that period is a gaping hole in the social security safety net, during which a claimant and their family, if they have one, may well be without any income whatsoever. Although the Government claims there is no link, the growth in the number and accessibility of foodbanks has helped ensure people in this position are unlikely to starve.

However their housing is a different matter. Universal credit, having replaced housing benefit, includes a payment for housing costs and in many cases that initial waiting period sees claimants run up a month-and-half of rent arrears.

Read more: Charity says new benefit is harming the poor

Housing Associations say that for people on minimal income, that initial accumulation of debt is difficult, if not impossible, to recover.

Critics of the system say it will leave many tenants prey to loan sharks or payday lenders, and that the stress of arrears is hardly conducive to finding work.

The Scottish Government does have powers to alter aspects of the way Universal Credit works, which should in theory mitigate the impact – by allowing the rent portion of the benefit to be paid direct to landlords, and varying the insistence that the benefit can only be paid monthly - helping those who struggle to budget.

The DWP says the system will be easier for people to understand and easier and cheaper to administer. It will make it easier for people to manage the move into work and encourage people on benefits to start paid work or to increase their hours.

Read more: Charity says new benefit is harming the poor

The experience of people in the seven areas of Scotland where ‘full service’ UC has been rolled out, will become increasingly clear.

If Citizens Advice Scotland is correct, people are being pushed into crisis and further poverty, rather than helped by the system.

Their evidence can be added to those of other groups including the Child Poverty Action Group in Scotland, several councils, housing associations, all of which say US is causing major difficulties.

CAS is calling for the roll-out to be halted. The Scottish Government has already done so.

But UC has been subject to considerable false starts and has caused major embarrassment to the UK Government already. Ministers are likely to resist calls for any further delays.