causeway

What was once Great Britain is now a quarantined island, cut off from the mainland and protected by an armed causeway that can only be accessed during low tide.

The tide recedes every day for a few hours, long enough to walk across a narrow strip of causeway to the mainland.

He's only ever known a feudal life in this 150-strong sanctuary, connected to the quarantined mainland by a single, heavily defended causeway that's only accessible at low tide.

He's only ever known life on an island connected to the quarantined British mainland by a single, heavily defended causeway.

They are a slightly lighter colour than the iconic hexagonal black basalt at the point of the causeway.