Please direct any concerns/queries/feedback to:
Andy Turner
http://www.geog.leeds.ac.uk/people/a.turner/
A.G.D.Turner@leeds.ac.uk

I wrote this readme.txt file to describe roughly what I did on 2007-01-24. 
What I did was some time ago and this is mainly from memory. 
Things have changed (I have tried grabbing some data again and the digimap interface seems different) and if you need something better perhaps I can find time to revisit this. 

I have found some copyright, terms and conditions via http://edina.ac.uk/digimap/ after using my athens login.

I plan to throw all the metadata in the zip file online and write a Web Page for you to refer to. Use the following URL:
http://www.geog.leeds.ac.uk/people/a.turner/data/OrdnanceSurvey/Meridian/
If it is from there that you read this and you want the data and are not from the University of Leeds and an Athens user, then let's contact EDINA and work out how best to do this. 

Rough outline of the processing:
1) Downloaded the tiled Meridian data via the digimap service (http://edina.ac.uk/digimap/) as NTF.
2) Used MapManager6.1 to convert the NTF to an ESRI format (I think shapefiles, but maybe e00).
3) Merged shapefiles together, selected the road lines and filtered these into seperate files. Something like the obs_acc_number variable (and meta data information explaining what obsaccno's refers to what). I've had a look and think this was something other than the meridian.pdf... Maybe something that I downloaded from OS directly... For this I think I used ArcView3.1 with some geoprocessing extension.

These steps were undertaken in parallel. At the time the data was too voluminous to store on my PC and process with the software I was using. It had to be done bit by bit. All the time I visually checked the results. Hopefully there is nothing missing, but there could be errors in there.

Hope this helps.