Lovell White Durrant and Freshfields are thrashing out the details of Rolls Royce's shock £576m bid for engineering group Vickers, after negotiations were completed in less than a week.
Lovells is representing Vickers while Freshfields is acting for Rolls Royce.
The deal will create one of the world's largest aeronautical engine and gas turbine manufacturers.
Originally only corporate partner James Reeves and consultant solicitor Dan Mace at Lovells acted for Vickers, which has been a client of the firm for 35 years.
Mace says: “It was just a team of two because it happened so quickly, we started on it last Friday (17 September).”
However, he says that given the scope of the deal the team has now expanded to include competition partner Philip Collins and share scheme partner Louise Whiteright.
Freshfields is representing Rolls Royce with a seven-strong team headed by corporate partner Graham Nicholson.
The team includes competition partner Nick Spearing, senior partner Anthony Salz, employment partner Nick Squire and tax partner Richard Ballard.
A spokeswoman at Freshfields confirms the team is likely to grow in size, but declines to comment further since the deal is ongoing.
As well as the sale of its aeronautical business, Vickers is expected to sell off its defence business to Rolls Royce later on this year for an estimated £100m.
Rolls Royce's bid shocked the City after negotiations for Vickers were completed in secrecy.
But there is speculation that Rolls Royce may not be the only bidder for the company, with rumours pointing to TI Group as a possible rival which counts Allen & Overy as its main legal adviser.
Vickers was once the UK's largest company but was worth just £300m at the time of Rolls Royce's approach.
Ironically, Vickers bought Rolls Royce's car manufacturing arm in 1980 which it then sold off to Volkwagen in 1998 for $790m (£494m) although the brand name was purchased by BMW for $66m (£41m).