A package of benefits was devolved through the Scotland Act 2016 in an agreement to increase Holyrood’s powers after the 2014 independence referendum.

The Scottish government had said it could set up a separate Scottish state for £200m in just 18 months during the campaign which preceded that poll.

But the experience of taking control of some parts of the UK benefit system suggests that proposition was wildly optimistic.

The handover process is taking far longer than anticipated and financial watchdogs say the set up costs for Social Security Scotland are now £685m.

Scottish ministers hoped to take over delivery of these benefits in 2020, but this commitment was dropped during the Covid pandemic.