The power of a pint of plain could play a key role in how Ireland votes in the second referendum on the Lisbon Treaty.

Padraig Cribben, chief executive of the Vintners' Federation of Ireland, which represents 5,000 publicans, says that plans to reduce the amount of alcohol that a person is legally allowed to drink before driving could play a significant role on how Irish people decide to vote.

"People in rural Ireland will see this as more of the nanny statism and it probably would affect the way they might consider voting in respect of the Lisbon treaty," he said.

Cribben went on to say that speed was the realt threat on Irish roads, and reducing the current alcohol limit would not have any effect on the number of road fatalities. It could, however, lead to the closeure or 1,000 public houses, he said.

The Road Safety Authority says even a single drink impairs driving by affecting the ability to judge distances and risks, and by slowing down decision-making.