France is blocking a post-Brexit financial services deal between the EU and the UK until Boris Johnson’s government grants fishermen fair access to British waters, officials have claimed.

French fishermen lack half the licences they need to fish in British waters and which Paris says are owed them after Brexit, France's government said Wednesday, adding it was working on possible sanctions that could affect power supplies to the UK.

France warned that the U.K. is in breach of the Brexit deal after it denied several small European Union fishing boats access to its territorial waters, ratcheting up diplomatic tensions between the two countries.

France has threatened to impose increased customs checks on goods coming from the United Kingdom from November 2 over an ongoing fishing row.

France might retaliate against Britain in a dispute over post-Brexit fishing licences by the end of next week, government spokesman Gabriel Attal announced Wednesday.