Hundreds of parents were sent into panic after a school went into lockdown.

The safety procedure was launched at St John's Church of England Primary School in Canterbury this morning after a child told their teacher they had seen somebody outside a window.

After a swift investigation found there was no risk to pupils, staff decided to continue with the lockdown as a practice drill.

A text message alerting parents to the incident sparked a flurry of anxious posts on social media, with many taking to Facebook to appeal for information.

The message, sent just after midday, said a "lockdown procedure" had taken place earlier this morning.

"The site has been checked and there is no risk to children," it continued.

A number of parents had been unable to contact St John's for further updates due to its phone lines being engaged.

Headteacher Jo Warnock says CCTV checks have confirmed that at no time was any unauthorised person on site.

"We are very proud of the way the children conducted themselves during this time and after a short interruption were soon able to continue enjoying World Book Day," she continued.

"We immediately contacted parents to inform them that St John’s had experienced a lockdown and there was no risk to children. This is in line with our school policy."