TfL's legal and compliance director Gareth John said the firms were chosen with a mind to the Mayor's strategy of achieving best value, diversity and sustainable procurement.
As reported by The Lawyer (30 July), John had insisted that prospective panel firms provide him with diversity statistics to help his decision-making process.
"We encourage our firms to reflect the values of diversity and sustainable procurement. All in-house counsel have a responsibility to do this," he said.
John added that the panel review allowed TfL and London Underground Limited the opportunity to clarify their expectations and ensure that the right mix of expertise and resource is achieved.
Among the projects on which the firms will be advising are the extension of the East London Line, the transfer and consolidation of the North London Railway and the extension of the congestion charging scheme.