'Every single one of us would rather be in school' - Hundreds of teachers locked out of schools
Everything you need to know
Hundreds of teachers across the capital were locked out of their schools as industrial relations within the education sector came to a head.
Teachers who are members of the ASTI union withdrew from working supervision and substitution hours - amounting to one hour per week - with a number of schools in Ireland now closed for health and safety reasons.
The union rejected the Landsdowne Road agreement, and because of this are not getting paid for supervision and substitution.
Despite the schools closing, teachers turned up in time for class and stayed for the duration of the first class outside of the school grounds.
English and special needs teacher at Colaiste Choilm boys school in Swords, Sinead Farrell said teachers are "disheartened" having turned up to teach.
"We're ready to work and the gates aren't open so it's essentially a lock out," she said.
"Teachers don't want to be standing outside their school with a lock on their gate but this is what we are reduced to now, this is what we have to do," she added.
Her colleague, Joan Parsons - an English and religion teacher - said "we'd all rather be inside".
"Every single one of us would rather be in school than standing out here," she said.
"There's a full compliment of staff, we've 21 classes at any given time so there's at least 21 teachers here," she added.
As many as 10 students arrived outside the school only to be turned away because it was closed.
Meanwhile, up the road at Loreto College, Deirdre Scully, who teaches English, Drama and has been a teacher there for 30 years, said her colleagues are "very unhappy" at the situation.
"We're not outside the door today over one hour at all, we've been locked out," she said.
"Tomorrow there will be a picket - it's about equal pay for equal work," she added.
Taoiseach Enda Kenny has taken a swipe at industrial action by teachers from the ASTI saying it "doesn't help" as the country tries to respond to Brexit.
He said that while Ireland is in "a position of some strength" the country "cannot be in anyway complacent about this."
Mr Kenny made the remarks at an Irish Times conference on Brexit this morning.
Minister for Education Richard Bruton told Newstalk Breakfast that the dispute is "absolutely unnecessary".
"The cause of the dispute is the withdrawal unilaterally of the ASTI of working one hour per week over the 33 weeks and that they work on activities that facilitate parents and children," he said.
"It is extraordinary that the union would close the schools indefinitely over their refusal to work those hours. Every other public servants works such hours - indeed they work many more hours.
"The disruption that is occurring for children, especially at this time when people are concentrating on exam preparation and trying to make their final choices after their mid term break, it is particularly disruptive."
Minister Bruton said that the impact on children is "devastating" and the notion of closing the schools is disproportionate.
"We made very effort to facilitate the schools staying open but the ASTI decided that they would not allow the principals to operate with the deployment of alternative staff."
When will the schools re-open?
At the moment, there is nothing to suggest that the schools will be in a position to reopen before the end of this week.
The closure of more than half of second-level schools, on health and safety grounds, arises from the refusal of the ASTI to continue doing supervision and substitution work.
What will happen when the schools close?
As well as disrupting students' education, activities such as sporting fixtures and rehearsals for school musicals, which take teachers' away from the classroom, are being cancelled.
The closures and uncertainty is also causing major headaches for working parents, who have to make alternative arrangements for their children's care.
Why is ASTI striking?
The withdrawal from supervision and substitution arises from the union's rejection of the Lansdowne Road Agreement (LRA) and a consequent decision to stop working the 33 Croke Park hours. ASTI members are alone among public service workers in not continuing to do this extra productivity which, in the case of teachers, amounts to one hour a week.
Because of this, ASTI members are not getting the benefits of the LRA, including payment for supervision and substitution, which triggered the union's move to withdraw from these duties from today.
Which school are closed?
Of the 97 community and comprehensive schools, 25 are closing today, five are opening on a partial basis with about 60 opening fully. Most schools in the education and training boards sector are unaffected, although some will close and some open on a partial basis.
The ASTI has told its members to turn up for work today and, if the school is closed, to remain until the end of the first class period.