Kids Across the UK Kept out of School in Strike Against Tests Petition signed by 40,000 says too many tests are harming UK primary school kids

 -- Similar to parent protests in the United States over standardized testing and the Common Core curriculum, thousands of United Kingdom parents have organized a strike against annual testing for elementary-aged children.

Children across the United Kingdom are skipping school today for "Kids Strike Day," which uses the social media tag #kidsstrike3rdMay, after more than 40,000 parents signed a protest petition.

Parents who joined a campaign called “Let Our Kids be Kids” published an open letter online to the Secretary of State for Education, Nicky Morgan, saying 7-year-old and 11-year-old children who have to take the SAT test -- which are similar to elementary school state tests in the U.S., not college board exams -- are "over-tested" and "over-worked."

"Children’s mental health is at risk because of the increased pressure they face through primary school testing,” the letter said, adding, “by the time these children reach secondary school they are turned off education.”

However, Britain's chief inspector of schools, Sir Michael Wilshaw, defended the importance of the tests, saying that children must have mastered the basics of reading, writing and mathematics by the age of seven to succeed later on.

"I understand testing can sometimes be stressful," Wilshaw said, "but I am also confident that most schools do everything they can to minimize the stress that children experience in preparing for and sitting these tests."

The Minister of State at the Department for Education, Nick Gibb, took to Twitter to urge parents to keep their children in school, saying tests are designed for schools to ensure that students are being taught the fundamental skills they need.

It is unclear how many children were on “strike” today but a website was set up for parents to record their participation.

A mother of five, Charlotte Furness, told ABC News why she supported the campaign.

"I am fed up of seeing more and more testing in schools," she said. "School is creatively restrictive already with the current testing schedule so adding even more tests puts so much extra pressure on teachers and children. They are squeezing the fun out of learning."

"We want to show the government that we are serious and by voting with our feet we hope to make them realise that as parents who care about their children's education, we won't stay silent anymore and just do as we are told," Furness added. "Our schools need a massive shake up and we hope today will show the government that we are prepared to fight for change."

Several local councils have warned parents that they could face fines for taking their children out of school without authorization.

A spokesperson for the Prime Minister told the UK Press Association that taking a child out of school for a day "can cause harm to their education," but added it was "a matter for schools to handle" whether any sanctions should result from students absence.