Jack McConnell has been warned he faces tough choices

It says that finding ways of paying for the spending commitments will dominate debates in the run up to the Scottish Parliamentary elections in 18 months time.

The research was led by Professor James Mitchell, of Strathclyde University, who said the executive's plans could pose a major challenge to new First Minister Jack McConnell.

He said: "These will limit his autonomy and may force a major review of spending commitments in the second half of the parliament.

"The costs of the combination of policies [former first minister Henry] McLeish took on create pressures that McLeish never addressed during his period as first minister."

Fear of shortfall

When the Scottish Parliament was set up it was given limited taxation powers.

The "tartan tax" allows ministers in Edinburgh to vary the standard rate of income tax by up to three pence in the pound.

Labour gave a commitment not to use these powers in its first term, but no guarantee has been given for the period after the next election in 2003.

Some economists have estimated the executive's commitments on teachers' pay, education, free care for the elderly and local government could cost nearly �2bn, leading to a potential funding shortfall.