North Sea crash: Cargo ship Solong being towed to Aberdeen

Burnt tiny plastic pellets, known as nurdles, have been washed up along the east coast in the aftermath of the collision.

Nurdles are balls of plastic resin used in plastics production.

Ernst Russ admitted they were held in containers on board the Solong and had been released during the intense fires, which took a week to bring under control.

According to conservation groups, the nurdles are not toxic but can have a devastating impact on animals if they are eaten.

Lincolnshire Wildlife Trust said a "clean-up operation has been underway for several days".

"Sadly the plastic pollution has been extensive at Gibraltar Point National Nature Reserve, where the shorebird sanctuary for rare and vulnerable species such as little tern and ringed plover is set to come into play from 1 April," the charity said in a social media post.

"Our priority at the Lincolnshire Wildlife Trust has been to clear this area ahead of the breeding and nesting season, when it is critical that the birds are not subject to disturbance."

It urged visitors to the site not to touch the debris.

Mr O'Callaghan said HM Coastguard was continuing "to support local authorities which are leading the onshore response to pollution, including plastic nurdles, in Norfolk and Lincolnshire."