On the night of 31 August 1940, the British 20th Destroyer Flotilla – consisting of HMS Express, Esk, Icarus, Intrepid and Ivanhoe – sailed from Immingham to the Dutch coast northwest of Texel to lay mines. The flotilla was joined by part of the 5th Destroyer Flotilla consisting of HMS Kelvin, Jupiter and Vortigern. While the ships were laying mines, air reconnaissance detected a German naval force moving west from Terschelling towards Britain; fearing an invasion the 20th flotilla was ordered to intercept.
Whilst heading for this possible invading German force, the flotilla ran into a newly laid, uncharted minefield and Express was badly damaged, losing most of her bow. The explosion caused heavy casualties: 90 of the 175 men on board were killed or wounded, including her captain, J.G. Bickford, who was injured by the explosion. The flotilla commander, Lieutenant-Commander Crouch, moved his ship, Esk, to assist Express but Esk also hit a mine and the vessel swiftly sank, killing all on board, except for one man. Ivanhoe then went to transfer the wounded from Express but also hit a mine and was badly damaged, the explosion killing a further 53 men and wounding the majority of the crew. Several life rafts, carrying shipwrecked sailors, drifted into the Dutch coast where those on board were detained by the German authorities as prisoners of war.
The 1st September brought Kelvin and Jupiter from the 5th flotilla to help rescue the shipwrecked crews and later two light cruisers – HMS Aurora and Galatea – arrived as an escort. Ivanhoe was scuttled by fire from Kelvin and the ships returned to port. Jupiter towed the hulk of Express until tugs could be sent out to take over. On the way, Galatea hit a further mine and was slightly damaged.
The final toll of the disaster was approximately 300 killed, with a further 100 injured or taken prisoner; this was the greatest loss of life suffered by Nore Command since the evacuation of Dunkirk. The German “invasion force” turned out to be a small mine-laying unit transferring from Cuxhaven to Rotterdam.