Clyde & Co and Barlow Lyde & Gilbert are in advanced merger talks, Legal Week can reveal, with a potential deal set to create a 300 million-pounds law firm in one of the largest-ever unions between two U.K. practices.

Senior partners at the two firms have been in discussions for several months, and it is understood that details of the proposed union could go to partners as soon as the end of June, when Clydes will hold its annual partner conference.