You can find more information on OpenData at the Ordnance Survey website.
These maps can provide a useful backdrop for your work. Here are some of the maps available directly from Ordnance Survey:
MiniScale (raster). A set of 4 maps, each covering the whole of the UK, showing major population centres and roads with or without grids and some contour styling. If you want something to display the whole (or large part) of the country, try this.
Open Street View (raster, 1:10,000 scale). This is the most detailed raster mapping available under OpenData. The granularity of download is 100 km x 100 km with files that can be over 1 GB - unless you have a fast broadband, you may wish to download these overnight!
Boundary-Line (vector). This contains all levels of electoral and administrative boundaries, from district, wards and civil parishes (or communities) up to parliamentary, assembly and European constituencies.
Code-Point Open (CSV). This comma separated value file contains all the postcodes for the UK by map reference.
1:50,000 Scale Gazetteer. This is in ASCII text with colon separated fields. It provides a list of over 250,000 place names by map reference.
Strategi (vector). This is vaguely the vector equivalent to the 1:250,000 Scale Colour Raster. It is ideal to get a regional overview of the road network, railway lines, cities and wooded areas.
Meridian 2 (vector). This is a 1:50,000 scale map, useful for overview and route planning.
OS Locator. This is in ASCII text with colon separated fields. It provides a national list of road names and their map references.
Land-Form Panorama. This is the only OS separate contour information, but is a VERY large download (530 MB). It includes spot heights and 10 m contours. It is also available as a gridded DTM with 50 m post spacing. It is a 1:50,000 scale.
VectorMap District (raster and vector). This is the most detailed vector mapping available under OpenData and roughly equivalent to a 1:50,000 raster.
Information on this site is copyright Dauntsey Drainage Board. Most of the maps are based on Ordnance Survey OpenData and additionally covered by that licence.