The Dublin Metro: The way is now clear for the Minister for Transport, Mr Brennan, to push the case for a PPP approach to funding the Metro, which would allow the State to pay off a contractor over 20 years or more.

However, the Department of Finance still has serious reservations about the cost.

The roads programme: The PPP pro-rater is already up and running in the national roads programme. The ruling will make it easier to plan finance for projects where motorists' tolls are not involved.

Schools and hospitals: The ruling clears the way for the State to get the private sector to build projects in these areas and then to lease them back over a period of years.

However, whether value for money can be obtained by doing this - or whether it would still be cheaper for the State to fund the projects itself - will be a key issue.

Cork School of Music: This PPP project has been delayed for three years and the Government has cited uncertainty over the EU rules as one of the reasons.

The way should now be clear for a go-ahead for the project, provided the Government is happy with the costs.

At the moment, 3,500 students are spread around 16 different sites, having moved out of the original building.

Other projects: The rules would make it easier for the Government to get the private sector involved in other areas, such as the provision of waste facilities and prisons.

The key will be whether agreements can be reached with the private sector to deliver such projects at a reasonable cost to the State.