Allen & Overy (A&O) has won an instruction to act for Russia’s largest steel company Severstal in its proposed €46bn (£31.5bn) merger with Luxembourg steelmaker Arcelor.

The deal, which will create the world’s most profitable steel company with a combined €46bn (£31.5bn) in sales and 70 million tones of production, was announced last week and follows a €25.8bn (£17.7bn) hostile bid for Arcelor by Netherlands-based Mittal Steel.