A Wakefield secondary school will be closed to all pupils tomorrow after suffering a ransomware attack.
St Thomas à Becket Catholic Secondary School, on Barnsley Road, said they had been forced to take the decision after discovering that the attack had "disabled all their systems".
This has left them unable to access their systems and monitor pupils, they said.
In a statement posted to Facebook, the school said they had been forced to reroute students to their form rooms every hour today (Monday, October 21), but this was not practical in the long term.
By closing the school for the day tomorrow, the school hope to restore their "registering, monitoring and safeguarding systems".
No personal data was accessed in the breach, the school said.
The full statement reads: "Pupils will be coming home this afternoon with a letter to say that unfortunately school is closed to pupils tomorrow (Tuesday 22 October).
"We discovered this morning that we have had a ransomware attack over the weekend which has disabled all of our systems.
"No personal data has been accessed in any way and is indeed completely secure, but we are unable to access our systems and cannot therefore track and monitor pupils through the day to keep them safe.
"As for today, we have rerouted pupils to form rooms every hour to re-register but this was a stop gap measure as sending them home without being able to contact all parents was not a viable choice for their safety.
"Whilst the investigation happens and the registering, monitoring and safeguarding systems are restored, we have therefore had to take the very difficult decision to close for a day to allow this process to happen.
"All of the pertinent authorities have been informed and the Trust have been fully involved with that process. We are sorry to families for the inevitable inconvenience this will cause."
According to Action Fraud UK, ransomware "is a form of malicious software that enables cyber criminals to remotely lock down or encrypt the files on your device. Criminals use ransomware to extort money from you (a ransom), and will claim to restore access to your files or device once you have paid.
"Ransomware can be delivered in various ways; for example, via attachments in authentic looking emails purporting to be from genuine companies."
According to Ofsted, St Thomas à Becket has a capacity of up to 750 pupils. The school became an academy in 2012.