Children at Blackhorse Primary School in Bristol will no longer be allowed to bring smartphones to school after a debate around safety was sparked when a pupil forgot to pick up their mobile at the end of the day.

For the past few years, students were permitted to bring smartphones to school but were required to surrender them to the teacher during class hours.

In one instance, a phone was inadvertently left in the teacher's cupboard overnight and was returned to the student the next day with a staggering 9,000 notifications.

The revelation of such intense activity on the Year Six social media group, coupled with concerns about potential cyber-bullying, sparked a discussion about whether smartphones should be allowed in schools.

Executive Headteacher Simon Botten, in a blog post, stated that the decision to ban smartphones was supported by most parents, although some expressed reservations about the move.

A similar ban is expected to be implemented at Blackhorse's sister school, Emersons Green, pending approval from the governors.

Mr Botten wrote: "The teacher picked up the phone, waking it, only to see a notification of 9,000 missed messages from the Year 6 pupil WhatsApp group overnight. Nine thousand messages in a 15-hour overnight period.

"After nearly two decades in headship, I have watched this technological phenomenon unfold slowly.

"At first it was imperceptible: the odd argument via old-fashioned texts, the odd child seeing something online which they shouldn't (always at home). But over the years I have seen the risks grow ever more significant and ever more frequent.

"A rise in cyberbullying on WhatsApp; of primary school aged children sending inappropriate images to one another; of children retreating into an online world and seeing less and less of their actual friends in actual parks; of children glued to their phones the moment they are given them back at the end of the day.

"And then something much darker. A rise in predatory strangers approaching children online in their bedrooms whilst their parents watch Eastenders downstairs. Near miss, after near miss. But, the thing is, if you have enough near misses – the chances of a collision rises to 100 per cent.

"So around a year ago, we started a debate at Blackhorse and Emersons Green. We sought to answer a simple question: should our schools become Smartphone free?"

Mr Botten went on: "Groups of parents were consulted on this issue before a wider consultation on the prospect of an outright ban.

"The safety argument was fairly understandable: how will I know my child is safe whilst walking to/from school if I can't contact them?

"Interestingly, we had several parents who were also police officers attend these discussions and their voices proved very persuasive, arguing that parents massively over-estimate dangers in the real world and massively under-estimate dangers in the digital world.

"We navigated this argument by agreeing that, if a child had to walk to school alone, then they could bring in a simple 'brick' phone (texts and calls only) which could be bought for as little as £10.

"We also reminded parents that the IMS app on their phone showed when their child was registered each day, and the school would always phone them (as we always have done) if their child didn't arrive at school.

"The second argument was centred around liberty and the school over-reaching its authority to dictate whether parents bought their child a smartphone. Quite rightly, the parents pointed out (in the nicest possible way) that this was none of the school's business.

"We countered this argument by explaining that we would not be preventing parents buying their child a smartphone, just preventing them bringing it to school.

"We made it clear that this was to support parents who wished to delay buying their child a smartphone by removing the peer pressure which existed on the playground before school where children would flaunt their smartphone prior to handing it in.

"It made it clear that the school would not tacitly condone smartphone ownership by collecting in children's phones each morning and then handing them back at the end of the day".

The school has also brought in specialists from the police to talk to parents about the dangers of children being unsupervised online.

Mr Botten explained: "The first step we took was to ask Avon & Somerset Police to lead a workshop for parents on the harms – in terms of sexual and criminal abuse – which they see as a result of predatory individuals approaching young people locally online. The parents, well over 100 from Blackhorse alone, sat in stunned silence.

"By the time the second repeat event at Emersons took place another 50 or so Blackhorse parents attended that one too – as word spread about the plain-talking police officer laying out for parents some of the real-world risks which they saw play out in Bristol every day.

"The police had far greater impact here than any educationalist. By the end there was a feeling in the room that something must be done – although at that point we didn't know what," he continued.

A survey revealed a strong majority of Blackhorse Primary School parents support a total smartphone ban, while opinions were more divided at Emersons Green Primary.

The governing body at Blackhorse decided with a vote that starting in September, mobile phones will be prohibited, while Emersons Green's governors have yet to cast their votes.

Mr Botten noted: "Since announcing the result, I have had zero emails from parents complaining about the ban, whereas I have had a good many parents thank the school for taking a stand.

"Parents expressed mixed emotions regarding the imminent phone ban; some endorsed it, while others highlighted the school's earlier stance promoting smartphone purchases for pupils.

Lee Budd, father of an eight year old pupil, Jonnie, commented: "I don't think it's a bad idea at all. Phones consume attention."

In contrast, one mother, whose daughter previously attended Blackhorse, remarked: "It was the school that encouraged us to get a phone for my Year 7 daughter so she could walk to school on her own.

"I feel neutral, really, but I don't see why they need to change the current rule of leaving the phone in a box at the start and end of the day. ".