No meetings are planned between ministers in Edinburgh and Whitehall to resolve the impasse over powers returning from from the EU after Brexit amid claims of a "power grab."
The Scottish Government last month rejected UK ministers’ proposals to amend the European Union Withdrawal Bill amid SNP concerns that it will mean 24 powers in areas like farming and fishing which should go to Holyrood, in line with devolution, are appropriated by Westminster. The Welsh government has accepted the deal despite similar concerns over a “power grab”.
Crunch talks in London last week failed to find a breakthrough.
"Time is very short," the spokesman said.
"I'm not going to put an arbitrary cut-off date on it and we're bound up with the Westminster process, the House of Lords process - it all gets very complicated in terms of the interlocking, over-lapping remit of Commons, Lords, devolved administrations and ultimately the UK Supreme Court as well.
"We've not given up, we're still looking to see if we can find a way through but given where things have reached there's no easy or clear path through this.
"The UK Government appear to have reached a point where they don't appear to be prepared to move further and we equally have a point of principle on the issue of consent."
"I'm just being realistic - at the moment I don't see any progress beyond where we were.
"It's possible there will be further ministerial contact, but there's nothing in the diary for a meeting or a call or anything like that."
Scottish Secretary Dvid Mundell will face a grilling on the issue from MSPs at Holyrood this week when he appears before the European Committee.
The stand-off centres on powers being repatriated from Brussels to the UK after Brexit and claims that responsibilities which should come to Holyrood in line with the devolution agreement are being appropriated by Westminster. UK ministers say they need control in these areas – such as farming and fishing – to protect the UK internal market during the immediate post-Brexit years.
New amendments from the UK government to introduce a “sunset clause” so that devolved powers returned to Westminster did not stay there indefinitely have been rejected. They also introduce a requirement for a “consent decision” at Holyrood before ministers can legislate in devolved areas. Ms Sturgeon said the definition of “consent” could even apply if the Scottish Parliament said no.