Bold plans for what has been described as the 'world's most ambitious undersea' project have been hit with delays. After decades of discussion, an underwater tunnel linking Spain with Morocco looked like it would finally be built before the 2030 World Cup.

The Moroccan National Company for Strait Studies (SNED) announced last year it was exploring finance options and 'strategic elements' of the infrastructure. While no specific costs have been confirmed, it's widely reported the project would total up to a whopping £6 billion.