Included in the Tory manifesto for the upcoming General Election, such intentions could be used to interfere in devolved policy areas and demand, for example, the introduction of water charges and increases in tuition fees.
Mr Durkan said: “In supporting the devolution of Corporation Tax, the SDLP also warned of the need for vigilance around the ‘balanced budget’.
“The SDLP was the only party to draw attention to this. We were right to do so, as the Conservative Party manifesto reiterates that the devolution of Corporation Tax is ‘subject to the Executive demonstrating fiscal stability’.
“When such a general conditional qualification is inserted in a manifesto we should not dismiss it as small print terms and conditions that might not arise.
“We know that they contrived budgetary strains for the Executive to induce Sinn Fein-DUP acquiescence on Welfare Reform.
“That experience shows that there is a clear and present danger that the Treasury will try to use the ‘switch-on power’ for devolved Corporation Tax rates to coerce other policy choices in the name of budget sustainability or fiscal stability.
“They could use this to interfere in devolved policy areas, preventing any element of devolved difference and demand the introduction of water charges and increases in tuition fees, for example.
“SDLP MPs will continue to hold the government to account on this at Westminster and SDLP negotiators will demand clarification and oppose any attempts to interfere in the Northern Ireland budget in the talks that resume after the election,” added Mr Durkan.