Merger talks between U.S. firm Hunton & Williams and U.K. firm Addleshaw Goddard have stalled following the U.K.’s June vote to leave the European Union.

Partners at the firms told Legal Week that the discussions, which were first reported in May of this year but are understood to have begun at the end of 2015, have slowed down in the wake of the EU referendum in order to assess the impact of Brexit on the U.K.