Seafish is in line for a £6m windfall after the Supreme Court ruled in its favour in the case brought against it by Bloomsbury International bringing to an end a three-year legal battle.

Seafish had been accused by the British Seafood Group subsidiary of illegally charging levy on imported fish. Following a ruling by the Court of Appeal in Bloomsbury's favour last March, the seafood body had been unable to charge levy on seafood landed outside the UK and then imported in.

Prior to the Supreme Court's ruling, it had been on the verge of having to draw down on government loans, admitted CEO Dr Paul Williams. "We wound our reserves down to the point where we had money for a few weeks and no more," he said.

It would shortly be writing to importers to request the backdated levy, he said, adding that they would not be unexpectedly out of pocket because Seafish had advised them to keep levy reserves.

The dispute began in November 2008 when Bloomsbury which is now in administration ­alleged that Seafish was ­illegally charging levy on seafood landed outside the UK. It claimed Seafish only had statutory authority to charge if the UK was the first place of landing.