Provides browseable TopoJson data for various types of boundaries in UK/GB.
GeoJson files extracted from the Geojson API provided at:
http://geoportal.statistics.gov.uk/ (for Great Britain)
http://osni-spatial-ni.opendata.arcgis.com (for Northern Ireland)
These were then converted into Topojson using: http://mapshaper.org/
The URLs of the raw files can be used to add these as layers onto a D3/Leflet map.