Sir Keir Starmer is on the verge of agreeing a major trade deal with the EU to boost arms sales - at the cost of concessions around fishing quotas in British waters.
The deal, The Times reports, will allow UK firms to sell billions of pounds worth of weaponry to allies in Europe.
But the agreement also comes at a cost for British fishermen, with part of the deal - largely pushed for by France - meaning a softening of the UK's stance on haddock, herring and cod quotas.
The existing deal, expiring next year, cut the amount of fish European fishermen are allowed to catch in British waters to 75% of pre-Brexit levels.
The Times understands the new trade deal will include a multi-year agreed freeze on fishing quotas, rather than further reducing European access.
The introduction of a fishing clause to the arms deal proved a curveball for some nations at the negotiating table.
Estonian top diplomat of the EU Kaja Kallas said she was "surprised at how important the fish are", with a British source telling The Times she was "speaking for all of us".