Greenberg Traurig Maher (GTM), the UK arm of US firm Greenberg Traurig, is set to become the first international law firm tenant of the Shard next month.

The firm’s five-year lease on its offices at 200 Gray’s Inn Road end in April. It has taken a 10-year lease for space on the eighth floor of the Shard and will relocate there next month.

The building is already home to IP firm Mathys & Squire, which focuses on patent and trademark law and is on the fifteenth floor, but GTM will be the Shard’s first full-service international law firm tenant.

The new office will give GTM room to expand beyond its current 40 lawyers but as the relocation coincides with Greenberg Traurig’s ongoing merger talks with Berwin Leighton Paisner (BLP), it raises questions over lease liabilities if the deal goes through.

Sources close to GTM suggest that in the event of a deal the merged firm could consider relocating a department to the Shard or subletting the space.

BLP is understood to have around three years left to run on its London headquarters at Adelaide House and is therefore likely to be considering a move from its London Bridge base or a renegotiation of terms over the coming months.

GTM is thought to be paying around £30 per sq ft for its Gray’s Inn Road office and was facing a significant rent increase, with costs likely to effectively double if it had remained, the consequence of rapidly rising mid-town prime rental costs.

If the Greenberg/BLP merger goes ahead it will create a 2,500-lawyer firm with nearly 750 lawyers in New York and London and a broadened platform across Europe, the Americas, Asia, and the Middle East.

Yesterday The Lawyer revealed that GTM’s revenue had risen by 10 per cent between 2014 and 2015, to £15.7m.