Northern Ireland political leaders are on a collision course with the Government accusing it of reneging on financial commitments and endangering thousands of jobs in the region.
They claimed the cuts unveiled by Chancellor George Osborne amounted to a £4 billion loss for the Stormont purse over the next four years, sparking predictions of 50,000 job losses.
First Minister Peter Robinson and deputy First Minister Martin McGuinness, who are returning from a US investment conference, said the cuts were worse than they feared and breached existing agreements.
But their criticisms brought a swift response from Secretary of State Owen Paterson who said the Government had fulfilled all its commitments and had reached a fair settlement with the Stormont administration, which local politicians must now allocate as they see fit.
Mr McGuinness claimed the coalition appeared to have reneged on an £18 billion investment pledge made by the British government in the 2006 St Andrews political deal that established the power-sharing administration at Stormont.
"I am very angry," he said. "I am going to hold my counsel on this until we have a full picture, but the initial reaction is one of great anger to the fact that it appears, at this stage, that Owen Paterson, who went on the record as saying they would honour the £18 billion commitment, appears to be far from honouring that position as we stand here today."
Mr Robinson said a 40.1% cut to the budget for infrastructural projects would stagnate the regional economy.
"I think there are two breaches of undertakings that we were given. Clearly there had been smoke and mirrors in relation to the £18 billion... on top of that, the Prime Minister had endorsed the Policing and Justice package, and we have very real concerns that there is a breach of an undertaking that was given in that area as well."
He told the BBC he feared the Government may fail to fulfil agreements made earlier this year in relation to the devolution of policing and justice powers to the Stormont Assembly.
But Mr Paterson said he had spoken to Mr McGuinness and Mr Robinson by telephone and he claimed they had failed to raise any concerns.