Platt was found guilty at Isle of Wight Magistrates Court today [Friday 23 June 2017].
The dad, 44, from Isle of Wight, had previously been fined £120 for taking his seven-year-old daughter on a holiday to Disney World in Florida in April 2015.
In May 2016, Platt won his appeal against the £120 fine in a High Court ruling, however, the Isle of Wight council asked Supreme Court justices to overturn the decision.
The Supreme Court justices considered whether or not Platt committed an offence by failing to ensure his daughter “attended school regularly”, as required by section 444(1) of the 1996 Education Act.
They ruled that “regular attendance” had to be keeping with rules of the school.
After the Supreme Court made their ruling, the case was returned to the magistrates’ court in the Isle of Wight.
The landmark decision is likely to affect millions of parents’ decisions about taking their children out of school to go on holiday.
It is hoped the Supreme Court will also provide some clarity on how much school can be missed before parents are prosecuted.
A Department for Education spokesperson previously told The Huffington Post UK: “The evidence is clear that every extra day of school missed can affect a pupil’s chance of gaining good GCSEs, which has a lasting effect on their life chances.
“We are confident our policy to reduce school absence is clear and correct.
“We are clear that children’s attendance at school is non-negotiable so we will now look to change the legislation. We also plan to strengthen statutory guidance to schools and local authorities.”