Leo Varadkar says it would cost between 10 and 15 million euro to reopen the tunnel and it would allow trains currently stopping at Heuston station, especially those on the Portlaoise line, to go on to Connolly station.

The big transport projects for 2012 include turning the sod on the Tuam-Gort motorway and the LUAS link up in the capital.

That will bring traffic disruption though, which Leo Varadkar says makes opening the Phoenix Park Tunnel more attractive: