The Ontario Labour Relations Board has ruled that strikes by high school teachers in three boards are illegal.

The ruling comes as back-to-work legislation is being debated in the legislature and is expected to be passed Thursday.

It’s not clear yet what impact, if any, the labour board’s ruling will have on that legislation, but the board has ordered a two-week moratorium on the strike at the Peel, Durham and the Sudbury-area Rainbow District school boards.

The school boards had argued that the three local strikes were really on central issues, and the labour relations board says it agrees in part, so it says the two weeks gives the Ontario Secondary School Teachers’ Federation an opportunity to “cleanse” the local strikes of central issues.

The labour board ruling does not permanently prohibit local strikes, whereas the back-to-work legislation would mean teachers in those boards can’t strike for the rest of the school year, even if a central, provincewide strike is staged.

Premier Kathleen Wynne says that once this “difficult” round of negotiations with teachers is over, she’s open to making changes to the process.