The waters off Northern Europe are littered with millions of tonnes of live, unexploded ordnance (UXO) — a legacy of two world wars and decades of government sea-dumping that continued until the 1980s, explains Simon Cooke, chief executive of UXO risk management consultancy 6 Alpha Associates.

“[Dumping ordnance] was not only irresponsible and short-termist, it’s now proving exceptionally expensive to deal with,” says the former British Army bomb disposal officer, who served in Afghanistan and Kosovo.