Only one in ten secondary schools make pupils hand in phones for the school day, a Department for Education survey suggests.
Polling of head teachers found only nine per cent require pupils to put phones into storage on entry, while only five per cent had banned them completely.
The vast majority – 75 per cent – said pupils could keep their phones on them, but not use them.
Teachers have previously said such rules are hard to enforce because it is impossible to watch every child all the time.
The survey, of around 550 secondary heads in the state sector, comes amid a judicial review claim by campaigners against the Government’s decision not to ban smartphones in schools by law.
Among them is Flossie McShea, 17, who said she was exposed to phone videos of porn and beheadings while at school.
Sir Keir Starmer has claimed that a new law is unnecessary because ‘almost every school bans phones in school; they do it already’.
However, today’s data, from the DfE’s annual National Behaviour Survey, calls this into question.
Only one in ten secondary schools make pupils hand in phones for the school day, a Department for Education survey suggests (pictured: campaigner Flossie McShea,17)
The polling also found only 15 per cent of secondary heads said pupils followed the school’s policy on mobile phones ‘all of the time’.
The report also surveyed 2,100 secondary school pupils, with only nine per cent saying they followed their school’s mobile phone policy all the time.
In fact, 34 per cent of pupils said they ‘rarely’ or ‘never’ followed it.
The findings suggest that even if pupils are told not to use phones, the temptation might be too strong if it is in their pocket.
Pete Montgomery, a father who is co-running the campaign, said: ‘This confirms what hundreds of thousands of parents and students know to be true: the Government’s current policy on smartphones in schools is failing to protect our nation’s children.
‘There are massive safeguarding violations, happening every single day, in every school where smartphones are allowed onto the premises.
‘The evidence is clear, and the solution is easy. Now is one of those moments in history where the government needs to step in: just like they did with seatbelts and smoking.’
However, while secondaries appear to be lacking in strictness currently, there has been an improvement on last year, when only three per cent demanded phones were given in and only 66 per cent prohibited use on school grounds.
In addition, a separate poll of 470 primary school heads show they are much more strict than secondaries, with 80 per cent saying phones must be handed in at the door.
The legal challenge against the Government is being mounted by Mr Montgomery, 45, and fellow dad Will Orr-Ewing, 40.
They want a total ban on smartphones in schools, although their proposal would not cover old-fashioned ‘brick phones’, which do not have internet access. They say allowing unsupervised access to the internet during the school day is a safeguarding failure because of the extreme content pupils are able to view.
So far, they have raised £28,960 of the £50,000 needed to follow through with the legal challenge, via a CrowdJustice crowd-funding page.
A Department for Education spokesman said: ‘Phones have no place in our schools, and leaders already have the power to ban phones.
‘Research from the Children’s Commissioner shows that 99.8 per cent of primary schools and 90 per cent of secondary schools already have policies restricting the use of mobile phones.
‘We support headteachers to take the necessary steps to prevent disruption, backed by clear guidance, and have also brought in better protections for children from harmful content through the Online Safety Act.’
