The survey work will move along the route in phases but, as it is taking place alongside a single carriageway section, traffic will be managed past the works by temporary traffic lights.

BBC: Investigation into flood-hit A595 in Cumbria

The debris survey team also deployed 400 numbered wooden blocks along the route, often near floating debris.

MSN: Survey Keeping Close Tabs on Japan Tsunami Debris

Mexico's large surplus is partly reflected in America's deficit: the route between Mexico and the United States is the second busiest for international traffic, after the route between Canada and the United States, according to the annual survey of global telecommunications traffic statistics, just published by TeleGeography, a consultancy.

ECONOMIST: TELEPHONE TRAFFIC