Charles Russell has just completed the biggest deal in its history with the u1.14bn takeover of employment agency Select Appointments by its Dutch rival Vedior.
The firm won the work through its close relationship with Select Appointments, which began when it handled a deal that rescued the company from bankruptcy in 1991.
"I don't think it ever occurred to Select to use anyone else for the deal," says Charles Russell corporate partner Simon Gilbert, who led the team that worked on the deal.
"I was never asked to put forward a proposal and I didn't have to beat anyone off, they just liked us.
"They just rang me one day and said "This takeover offer has come in - can you get over here in the next two or three hours?'
"This is the biggest deal the firm has ever done."
In the 1991 deal, Charles Russell acted for Swiss head-hunter Martin Pestalozzi who bought a 90 per cent share in the struggling company for u2.5m. Pestalozzi stands to gain u400m in cash from the takeover.
Since 1991, the firm has handled the company's NASDAQ flotation and all its mergers and acquisitions work.
Gilbert worked on the deal with fellow Charles Russell partner Katie Knight.
Vedior was represented by Allen & Overy, with partners Cindy Cook and Alan Paul leading the team.
The takeover will create the world's third largest employment agency, behind Manpower and Adecco.
However, the takeover may mean that Charles Russell has to fight harder to keep the UK work.
"I hope we will keep the UK work, I realised that there is going to be a lot of competition for the work now," admits Gilbert.
Mayer Brown & Platt carried out the US law side of the deal for Select Appointments. London-based corporate partners Mark Uhrinuk and Richard Cole led the team.