Based on Jason davies answer .
The problem is that you are converting non-projected TopoJSON (geographic coordinates) to SVG.
You need the last topojsoncode:
sudo npm rm -g topojson
sudo npm install -g topojson
topojson --version
Should be returned +1.6.12.
uk.json, topojson. TopoJSON SVG topojson-svg.
curl -o uk.topo.json 'http://bost.ocks.org/mike/map/uk.json' #get an online topoJSON file
topojson uk.topo.json --projection='d3.geo.mercator()' -o out.topo.json #works !
topojson-svg -o output.svg out.topo.json #works !
:

uk.topojson, 2 , 2 topojson, object-places. .