CMS Cameron McKenna has landed a lead advisory role opposite Allen & Overy (A&O) on the proposed merger between United Business Media (UBM) and business data provider Informa – with the deal set to create a media giant with a combined value of more than £3bn.

Camerons is understood to be acting on behalf of Informa, with corporate partner Gary Green thought to be leading the team.

A&O is representing UBM, with corporate partner Ian Lopez leading the team for the magic circle firm. He previously advised UBM on the 2005 sale of market research business NOP World for £383m.

UBM has also previously turned to firms including Ashurst for corporate advice. Ashurst advised the company on its £248m sale of a 35% stake in Channel Five Television in 2005, with Linklaters acting for long-term client RTL as buyer.

Talks between UBM chief executive David Levin and Informa executive director Peter Rigby are reportedly still at an early stage, with private equity giant Apax Partners cited as a potential rival bidder for Informa. Apax already owns Legal Week parent Incisive Media, as well as the former trade publishing division of Emap.

Informa has been subject to takeover talk over the last few months, having accrued debts of around £1.1bn following the acquisition of Datamonitor, conferencing company IIR and Taylor & Francis.

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