A centre for children with special needs, pioneered by millionaire businessman Mr J P McManus, has been extensively damaged in an arson attack.
More than €500,000 worth of damage was caused to the new therapy clinic at St Gabriel's school and centre for children with special needs, in Dooradoyle, Limerick, following Tuesday night's blaze.
The new €3 million wing was due to open in July but up to half of the 9,000 square foot unit was completely destroyed in the fire, which gardaí say was started deliberately.
More than 300 children with special needs use therapy services at St Gabriel's centre and a further 38 children are in full-time education at the school. The existing school building was not damaged in the blaze.
The manager at St Gabriel's, Ms Maire O'Leary, said the fire was the worst thing she had to deal with during her 12-year tenure.
"I know no one has died and thankfully nobody was injured but in terms of what we are about it's a terrible setback. Everything was going so well and we were picking out paint colours only on Tuesday.
"The builders are very upset too because they have taken great pride in this project." It was hoped that the new centre would serve the 300 outpatients along with the 38 students at the school.
"All of our students would have learning disabilities and a physical disability, along with our day patients at the centre, so we need a lot of space.
"The centre we have at the moment beside the school is very cramped so we were looking forward to moving into the new unit," said Mrs O'Leary.
Mr McManus helped raise €600,000 for the unit through a Golf Pro-Am in Limerick, featuring Tiger Woods and Mark O'Meara.
Attempts were made to start two separate fires at the school but one of them failed to ignite.
A 19-year-old man was last night being questioned by gardaí in connection with the blaze.