Go to any educational technology conference these days and you will eventually hear someone claim: “In the future, we will teach using the mobile phones kids bring into school.”

Just a few weeks ago, TES Magazine ran an article on how ICT expert Professor Stephen Heppell believes schools should encourage pupils to bring and use their own kit rather than invest heavily in ICT.

The idea seems like a good one at face value. Schools have indeed invested heavily in ICT and they are still miles behind the state of the art. Children always have the latest stuff and we can’t stop them bringing it to school: “Let’s use their mobiles as classroom ICT equipment.” It sounds great, right?

Kids love their mobile phones, it will save money and the IT manager won’t block it.

But the idea is both wrong in principle and unworkable in practice. I say this as someone who, at some point each week, fulfils the role of ICT director, policy writer, classroom teacher, software developer, systems administrator and frontline technical support.

The “run what ya brung” movement is dangerously wrong: it purports to save money while hiding huge costs elsewhere. It also relies on a number of assumptions that are difficult or impossible to justify, except by framing the argument in an indefinite “future” timeframe.

To be clear, I am not arguing for a ban on mobile phones in school. On the contrary, I am glad to use them as an additional capability in my classroom. What I am against is the assumption that they should become the front line of ICT provision in schools.

First, it assumes that every pupil has a mobile phone. This is probably the least troubling of all the embedded assumptions. Most pupils will have a mobile phone. But there is an element of “let’s base our lessons on some huge assumptions about the economic status of our pupils’ parents”.

It also takes for granted the idea that every pupil’s mobile phone has a particular baseline capability.

It is easy for someone not familiar with technology to wave a hand and say, “Even the worst mobile phone can do XYZ”. But when it comes to delivering a lesson using those mobile phones, the situation is a lot more complicated.

How do you deliver a session that is just as good on a three-year-old BlackBerry as on the latest iPhone 4? What about the kid with the Sony Ericsson W910i that can only access WAP? And what about the child who dropped his phone, leaving two of its keys out of commission? Or the youngster with the phone whose battery can’t last a day on standby, far less a morning of continuous use?

Even if these issues are surmountable - which they aren’t - who would be happy teaching to the lowest common denominator? Or happy that this was being advocated as the “cutting edge” of educational technology?

The theory also assumes that every mobile phone has internet access.

I would be willing to bet that there are pupils with web-capable phones whose parents aren’t paying for anything more than a voice contract, and I can guarantee that there are pupils who don’t have web-capable phones at all.

Only a small proportion of all phones have Wi-Fi. And even if you manage to get a class where everyone has a phone with Wi-Fi capability, do you think your system administrator is going to let them connect to the same network as your school’s management information system? I doubt it.

Furthermore, not all pupils will be happy to use their mobiles in this way.

Are you happy to hand over your iPhone to a stranger? If you’re 15, there will probably be some compromising material on those devices. Some flirty texts? Drunken photos? Web history? Your Twitter and Facebook apps with stored passwords, allowing anyone in control of your mobile to access your account?

If the “run what ya brung” movement ever gets off the ground, I’m pretty sure you will start to see children adopting “burner” phones - cheap models that can’t be traced back to them, just like in The Wire - just to use in class.

Asking pupils to bring in their own equipment also betrays a lack of confidence in schools’ existing technology. Many schools spent incoherently - and often overspent - during the Labour bubble years and there is now an expensive interactive whiteboard in every classroom, whether it is wanted or not.

Many schools have bits and pieces of technology lying around but no consistent idea of how to apply them. There are Nintendo DSs, Wiis, Xboxes, Windows PCs, laptops, iPAQs, AlphaSmarts, interactive whiteboards and classroom voting systems. Each corresponds to an era of technological fashion in education - and, crucially, none has produced lasting change.

But the stumbling block that kills the whole idea of using pupils’ own mobile equipment stone dead is that it assumes that teachers will be aware of the differences between devices and able and willing to plan around, or overcome, them. The dark underside of the proposal is that it tries to bury the cost of ICT in the cost of general staff time and effort.

Software developer Bob Ippolito once wrote: “If you put enough `almost works’ things together in a particular way, then you end up with something that approaches `works’ as effort goes towards infinity.” Software developers and system administrators know this. They have the scars to show for it. Many teachers and educational technologists - I can only assume - have never managed a heterogeneous hardware environment.

I assume this because nobody would advocate it if they had to be personally responsible for delivering a working education system out of an unknown and constantly changing bag of components that they don’t own, don’t control and can’t test.

Just visit your nearest mobile phone shop and ask the assistant to explain the technical differences between their five bestselling phones. Good luck designing a meaningful and worthwhile ICT lesson that works equally well on those five devices, never mind the vast array of equipment that you might be confronted with in your classroom.

Does anyone believe that the teachers who have hitherto refused to adopt educational technology will accept this kind of additional burden? We ask teachers to differentiate their lessons based on age and ability; are we now asking them to differentiate them for the device each pupil carries? Even if the majority of teachers were technically capable of doing so - which, in the main, they are not - it is wrong for technologists to abrogate their responsibilities in this way.

We have come too far to retreat to a position where individual teachers are responsible for figuring out how to deliver relevant lessons using technology appropriately. That was the 1990s - the geeky teachers did well and the rest struggled with or ignored ICT. We cannot now walk away and tell pupils and parents that it is their problem and they must provide ICT to schools.

- Fraser Speirs is head of computing and IT at Cedars School of Excellence in Greenock and is also responsible for IT provision, policy and strategy

SPEIRS IN BLOGS AND TWEETS

- I started saying “handwriting is dead” in my presentations - for the shock value. You know what? Nobody finds it shocking. @fraserspeirs

- When the entire educational experience is designed around the assumption that there will be 1:1 technology, it’s simply unacceptable for a pupil to be without a device for an entire day or more. Extract from speirs.org

- “Because of the exams” is now by far and away our #1 reason for not using technology in senior classes. @fraserspeirs

- “Many . focus on a “back to basics” approach to education: back to pencil, paper, mental arithmetic, paper books. I’m increasingly coming to believe that there are `new basics’ to teach.” Extract from speirs.org

- Follow Fraser Speirs on Twitter at @fraserspeirs, or read his blog at speirs.org.