Containers in UK waters 'no surprise', Southampton expert says

Boxall said the figures may be far higher and "there are dangers environmentally as the contents can be very damaging".

"Some contain chemicals, weapons, you name it they go in containers," he said.

He also highlighted a lack of accountability, as there was previously no legal obligation to report container losses in international waters.

"This raises serious concerns for navigation as they sink below the surface for some time before they come to the seabed," he said.

"Anything that hasn't been logged presents an unknown hazard to the environment and shipping."

The International Maritime Organization introduced a change in the law from 1 January, making it compulsory for ship masters to report all losses "without delay and to the fullest extent possible".

Boxall said the issue was "not going to go away", as UK imports were increasing and there was a pressure to turn ships around quickly.

He added that the change in legislation would help to "raise awareness of the true size of the problem and could lead to further action" in the future.