Cobbetts and Pinsent Curtis have fought off four firms to snatch the lion's share of property work for Lancashire County Council's pension fund.
The two firms competed against Nabarro Nathanson, Eversheds, Dibb Lupton Alsop and Pannone & Partners in the three-stage tendering process which began in May.
The majority of work was previously handled by Nabarro Nathanson while Linklaters & Alliance, Dundas & Wilson and Slater Heelis, which merged with Cobbetts last year, also provided advice.
Ian Fisher, legal services manager at Lancashire County Council, says more than 25 firms applied for the work, but only six were invited to tender.
"It was very difficult as all six were very good. We had to work out that we were getting the right deal with the firm and helping the pension fund receive the best care," he says.
A Nabarro Nathanson spokesman says: "While it is disappointing to lose a client it is balanced by recent panel appointments to The Ministry of Agriculture, Fisheries and Food and the Department of the Environment, Transport and the Regions."
Under the new line-up Fisher says both firms will handle about 50 per cent of the property work for the pension fund each.
However, he says the percentage could change as the council will continually monitor Cobbetts and Pinsents' progress. Fisher says it is difficult to predict how much the work is worth but says two years ago the firms netted between u250,000 and u350,000.
The review took place as responsibility for the legal panel shifted from the authority's treasury group to the legal department under the Labour government's Best Value tendering initiative.