Dublin's St Patrick's Day parade will be less spectacular than last year's - and the Luas is to blame, say organisers.
The Department of Transport has said that due to safety concerns, it cannot sanction the taking down of Luas cables running across O'Connell Street for the duration of Thursday's parade.
It says power will be switched off as floats pass along the street.
The department has advised organisers that displays and floats must be lower than 5½ metres to pass safely under the cables that run across O'Connell Street at Abbey Street.
A spokesman for the parade said that last year's floats were up to 12 metres high.
"Participating pageant companies have made the necessary last-minute adjustments so people will still be able to enjoy the parade, but we are concerned that in future years both the scale and spectacle of the world-class parade will be diminished and the public might lose interest in what has until now been a day to showcase the creative talents of Ireland," he said.
Chief executive of the St Patrick's Festival Donal Shiels said it was the Luas's "national duty" to take down the cables.
"The Luas have known about this issue for some time now. I understand that to take down the Luas overhead cables would take no more than five hours.
"On the one day of the year when the whole world watches Dublin, it is not an unreasonable request to let our national celebrations pass without having to worry about overhead restrictions," Mr Shiels said.
He said that since the parade started more than 75 years ago, all of Dublin's transport agencies had happily agreed to amend their services on March 17th to facilitate the parade.
Dublin Bus had moved its terminuses and Bus Éireann had diverted bus routes.
"And while the Luas have agreed to turn off the power in the overhead cables, they will not, despite repeated requests, take the cables down."
A spokesperson for the Department of Transport said organisers had been told in 2003 that the cables could not be removed as it would cause major disruption and have safety implications for the service.