The Scottish Government could launch a formal dispute against a £1billion deal that will see the DUP prop up a Tory administration at Westminster.
A number of prominent SNP figures have argued the agreement to allocate an extra £1billion in funding to Northern Ireland should mean an extra £2.9billion coming to Scotland as a result of Barnett Formula rules.
Ministers will now consider invoking a “dispute resolution mechanism” through the Joint Ministerial Council (JMC), the body that deals with matters between the UK Government and devolved administrations.
A spokesman for the First Minister said: “As well as writing to the Treasury today it is likely the Scottish Government will be invoking the UK Government with a view to invoking the dispute resolution mechanism under the JMC process.
“Cabinet expressed its displeasure at the nature of the deal with the DUP, which would appear to be a gross breach of established principles of devolution.”
Scottish Secretary David Mundell previously said he would not support funding which “deliberately sought to subvert the Barnett rules”.
Speaking last week, he added: “We have clear rules about the funding of different parts of the United Kingdom.
“If the funding falls within Barnett consequentials, it should come to Scotland.”
However, Downing Street has argued that as the funding will not be handed over via Barnett, it will not be subject to the same rules that usually govern payments to devolved parliaments.
In a similar way, they suggest, the formula did not apply to city deals in Scotland and Wales that saw hundreds of millions of pounds paid out for localalised projects.
Aberdeen South MP Ross Thomson said it was “absurd” for the SNP to criticise UK Government spending on top of Barnett in Northern Ireland “when the exact same thing happens in Scotland”.
However, Ms Sturgeon claimed the “grubby, shameless deal” showed the Tories “will stop at nothing to hold on to power – even sacrificing the very basic principles of devolution.”
She added: “By ignoring the Barnett formula, Scotland will be missing out on an estimated £2.9bn in funding for our public services – that is the price to Scottish taxpayers for the Tories to stay in power.
“This breaks the very principles that underpin devolution and the funding settlement the Tories pledged to protect.”