The Manchester firm joined up with sole practitioner and former local government chief officer Robin Mosley in order to pitch for the work.
Mosley worked at Walsall Metropolitan Borough Council in the 1980s.
The deal involved the sale by the council of an area of Digbeth town centre to Norton & Proffitt (Developments).
Stephen Kinsey, property investment partner at Cobbetts, says the firm has never undertaken work in the Walsall area and would not normally have tendered for work in the region.
Mosley says: “I was approached by Walsall to tender for the deal but I appreciated that it was a big job.
“I had links with Cobbetts and I made a proposal that they could provide additional members of the team.”
However, Nigel Watkins, senior property partner at Eversheds, says: “On this particular scheme I would have been surprised at a sole practitioner being invited to tender.
“As I recall, it was a reasonably sized project. A sole practitioner might not have the resource to cope.”
Mosley denies he secured the job because of his former links to Walsall: “There are no lawyers I know left there. I do legal work for local authorities in general.”