The fourth mainland tunnel attempt

A new public-private consortium proposes a freight-first connection.

Electric shuttle trains, modern emergency systems and a dedicated mainland terminal are supposed to avoid the failures of earlier schemes.

Old workings are surveyed as liabilities. They do not form a usable route.

The consortium develops a fresh alignment, constructs a mainland service shaft and prepares island launch facilities.

Ground movement during pilot excavation forces a stoppage in 2021.

An independent review concludes that sections of the rock cannot meet the promised tolerances without major redesign.

Insurance costs rise. Terminal land becomes the subject of litigation. Investors refuse another open-ended delay.

The project is cancelled in 2023.

It leaves warehouses, unused junctions, launch pits, compensation disputes and expensive equipment awaiting disposal.

Passengers and freight continue crossing by sea or air.

Later promises to revive the scheme are not a fifth construction attempt unless new work actually begins.