The M3 forms the southerly part of a E-road network which is how long?
M3 motorway (Great Britain):  From Junction 9 (A34) near Winchester, to Junction 14 (M27) on the northern fringe of Southampton, the M3 forms the southerly part of the unsigned E05. European route E05:  The route is 1,900 mi long.
1,900 mi long.