I misremembered slightly: it was a Norwegian tunnel, not bridge.
https://news.sky.com/story/thames-tunnel-project-delayed-after-planning-it-cost-more-than-worlds-longest-road-tunnel-13230526
National Highways revealed in a Freedom of Information (FoI) request earlier this year that £295m has been spent on the application process for the LTC. Overall spending, including technical surveys and land purchasing costs, has surpassed £800m - all before a spade has hit the ground.
As pointed out by pro-growth campaign group Britain Remade, the planning fee alone is more than twice the cost it took Norway to actually build the longest road tunnel in the world.
The Laerdal tunnel, connecting Oslo and Bergen, only cost £140m, adjusted for inflation, the thinktank's head of policy Sam Dumitriu said.