Helping pupils work more neatly - Why is maths done on squared paper?

Update November 2013 - turns out that while students do appear to work more neatly on lined paper (purely a subjective view), they also seem to work much BIGGER. The result is them filling exercise books about 30% more quickly than they did with the squared paper (again a subjective generalisation, but noticeable across groups and the whole school). The neatness may improve but the basic quality of the work and hence the assumed quality of the learning is fairly similar. As a result we have just decided as a department to revert back to squared paper - mainly to slow down the consumption of books and the resulting growth in departmental spending! We'll just have to go back to policing the neatness...

Fairly short one this - bit of a work in progress actually, but showing good signs of positive effect...

Background
Standard practice in our school, and in every maths department I've ever seen in a UK school is to ask students to work in books with squared paper. this can be 5mm squared or 10mm squared, but it's always squared. We used 5mm squares.

However I often find that students struggle with this - the presence of the vertical lines seems to negate the horizontal ones in terms of organising their written work which can weave around all over the place. This is particularly true of weaker students or for students that struggle with presentation.

I thought about this for a while and it occurred to me that we only occasionally actually make use of the squares (drawing graphs, diagrams), otherwise the squares are a bit of a distraction for written work and note taking. We also have the issue that students often work more neatly when they draw a margin on the pages, but then we get into a battle of wills to insist that one is drawn (as it's impossible to buy a squared paper book with a printed margin).

On the other hand exam papers in the UK always give either completely blank space for working or a lined space. If a squared grid or graph paper is needed then it is explicitly printed into the papers. Similarly once you depart from the world of education it is very rare to come across squared paper unless you specifically need it.

So why do we persist with squared paper in classrooms?

I raised this in a department meeting and as a team we decided to stop with squared paper. As such our last delivery of exercise books was just lined, with a pre-printed margin (we've found they're also slightly cheaper than squared paper books - for those of you that are looking to shave down your departmental budgets!).

It's early days still - they're still rolling out across the department as students use up old books, however with about 30% of our students now on lined books the change does appear to be quite marked...

Students who used to scrawl all over the place on squared paper suddenly start writing on the lines (as they're trained to do in every other class where they need to write something down). This is purely a subjective thing, but the books with lined paper do look neater.

Speaking to students they much prefer to write on lined paper, and they say it's easier for them to organise their work.

What happens when they do need to draw a graph or need to use squared paper? the answer is obvious - We just give them a loose piece of squared or graph paper to stick into their lined book.

Is this purely about appearances?
Not really - it's about helping the students to make clear notes that they can understand, and can show their workings in a clear way.

Summary
1) The student's work is neater and more readable (so far this appears to apply across ability ranges and genders) - I've not got any pics to illustrate this but will try to grab some and update the post with them in due course.
2) The students say they prefer the lined books to work in
3) Lined paper matches the format given in exams and the likely paper available outside of the school environment
4) The lined books are cheaper

So why do so many maths classrooms persist with squares?

All thoughts welcome...