On 10/10/2012 17:37, Basil Jet wrote:
On 2012\10\10 15:58, Roland Perry wrote:

Especially as I've taken pains to explain the tunnel was built in the
middle of nowhere (at the time) and the ferry connected existing
built-up areas.

Why was it built in Dartford though, when a tunnel from Gravesend to Tilbury
would fit in much better with the pre-M25 road network... or was it because
the M25 was already planned when the first tunnel was dug.

The tunnel did not directly connect inner-urban areas (the ferry still runs
from the centre of Gravesend to (more or less) the centre of Tilbury. That,
in the 1960s, would not have been a good plan for a road crossing of the
river. Connecting open countryside (and the A2 and the A13) was a better one.