Nine months of talks between the U.K. and European Union over a post-Brexit trade accord are hanging in the balance, with officials trying to bring them to a conclusion as soon as Wednesday. Prime Minister Boris Johnson and European Commission President Ursula von der Leyen intervened personally Monday and Tuesday, holding several phone conversations in a last-ditch bid to reach an agreement before the U.K. leaves the single market at the end of the month.

European Commission President Ursula Von Der Leyen News Conference

Ursula von der Leyen in Brussels on Dec. 21.

Photographer: Thierry Monasse/Laposte/Bloomberg

Negotiations resumed early on Wednesday in the Commission’s Berlaymont headquarters in Brussels, but people close to the discussions played down suggestions a deal is coming imminently.

The discussions are focused on two key disagreements over fish: what access EU boats will have to British waters, and what rights the EU will have to impose retaliatory tariffs should the U.K. limit that access in the future.

Both sides have made an agreement on fishing a precondition for any wider deal over their future relationship, even if the 650 million euros ($790 million) of fish EU boats catch in U.K. waters each year is a fraction of the 512 billion euros of goods traded between Britain and the bloc each year.

Michel Barnier, the bloc’s chief negotiator, told a meeting of ambassadors from the bloc’s 27 member states Tuesday that there has been progress in the talks, and a deal could be signed before Christmas — if the British are prepared to compromise further on fishing, according to diplomats briefed on the discussions.

After Christmas?

The talks could still continue beyond Christmas, or fail completely. Senior EU officials said the decision lies with Johnson, while people familiar with the British side said the onus was on the bloc to move.