Problems about blue water running from the school's taps emerged in mid-2018, and by December, North Lanarkshire Council had started replacing 1,800 metres of copper piping to resolve the problem.

The authority told unions, staff and parents in November 2018 that the pipes had corroded and led to the discolouration of the water, and of the plan to replace copper pipes with plastic.

Panic erupted after reports in May 2019 that teachers had been diagnosed with bladder cancer, and a parent said her son had lost his sight.

Some said that the site's former use as a deposit for waste from Gartsherrie Ironworks from 1945 to 1972 was to blame.

Fears were so high that the Government commissioned an independent review after officials were called liars during a public meeting.

The NASUWT members first walked out on June 20, which forced it to close early for summer.

Over July, indepedent experts tested the site and spoke to those who felt their problems had been linked to the school.

The report published on August 9 acknowledged there was one area with "higher than expected concentrations of polychlorinated biphenyls" and advised the council to fix the issue, which they did the following day.

It found no link between the health concerns and the blue water, or environment.

Some parents are calling for their children to be tested. However, medics questioned what they would be testing for given there is no evidence of problems at the school.

Others claim the Government's review was a "whitewash" and is an attempt to cover up problems with the site to avoid costly legal bills.