Various Metro projects for the capital have been proposed in recent decades, but none has yet proceeded to build stage.

The 18.8km MetroLink rail line, most of which will be underground, is to run from north of Swords to Charlemont

Darragh O’Brien said the MetroLink ‘would not be replaced by self-driving cars’, as suggested by Dermot Desmond.

The revamped National Development Plan is to be announced on Tuesday.

In contract discussions, Sean Sweeney asked as well if he could be paid a car allowance instead of being provided with use of an electric vehicle.

The €9.5 billion Metrolink is set to run from north of Swords to Dublin Airport

The planning hearing is scheduled to last about six weeks.