* Deal will make Hutchison biggest UK mobile operator
* Bid comes amid tougher EU regulatory environment
By Foo Yun Chee
BRUSSELS, March 7 - CK Hutchison Holdings Ltd said it had"fruitful" talks with EU regulators at a hearing on Monday aimedat dispelling antitrust concerns over its plan to become the topUK mobile operator by buying Telefonica's O2 unit.
The deal is crucial to Asia's richest man Li Ka-shing's planto expand Hutchison's telecoms footprint across Europe andfollows two other takeovers in recent years.
The company set out its arguments at a closed door hearingon why the European Commission should approve the deal withoutdemanding too many tough concessions.
"Today's hearing has given CKHH the opportunity to haveanother fruitful exchange with the Commission and the MemberStates' representatives concerning its proposed acquisition ofO2 in the UK," Hutchison said in a statement.
Participants at the event included senior Commissionofficials, national competition agencies and executives fromBritish pay TV company Sky, Liberty Global,TalkTalk, Vodafone, BT and TescoTelecom, according to people familiar with the matter.
British consumer electricals and mobile phone retailerDixons Carphone and French telecoms billionaire XavierNiel's Iliad, which is also eyeing the British market,were also present.
UKB Networks and Gamma completed the list of rivals whichcould scoop up any assets Hutchison may have to divest in returnfor EU regulatory approval. The company submitted a package ofconcessions last week, but did not provide details.
The deal, which will cut the number of British mobilenetwork operators from four to three, has already triggeredregulatory concerns after other similar mergers resulted inprice hikes.
Hutchison's biggest hurdle is its network sharing agreementwith BT's newly acquired mobile operator EE and Telefonica'smobile towers sharing deal with Vodafone, according to analysts.
($1 = 0.7010 pounds) (Editing by Julia Fioretti and Alexander Smith)
Vodafone (VOD)