MOBILE network operator Vodafone is considering launching a daring bid to buy smaller rival T-Mobile UK, in plans that could bring it face-to-face with competition regulators.<br /><br />The world&rsquo;s largest mobile network by revenue is kicking the tyres at underperforming T-Mobile UK, which has an estimated enterprise value of around &euro;4bn (&pound;3.4bn).<br /><br />Such a deal would give rise to a giant combined entity controlling at least 40 per cent of the UK market, dwarfing rivals like O2, currently the biggest UK mobile network by market share, and French-owned Orange.<br /><br />As well as attracting attention from competition authorities, O2&rsquo;s Spanish owner Telef&oacute;nica and Orange&rsquo;s owner France Telecom would be likely to lead calls for the deal to be vetoed.<br /><br />Smaller market participants like 3, which controls around 8 per cent of the market, would also be likely to campaign for potentially costly and long-term legal procedures.<br /><br />However, if Vodafone could guarantee the firm&rsquo;s market share would not exceed a certain critical point under any merger or joint venture, it might be able to force a deal through.<br /><br />Currently, single operators have market shares of around 40 per cent in France, Italy and Spain.<br /><br />Ren&eacute; Obermann, chief executive of Deutsche Telekom, which owns T-Mobile UK, has appointed US investment-banking giant JP Morgan to advise it on options for the struggling mobile network.<br /><br />T-Mobile UK has failed to keep up with some rivals during the recession and in the first quarter of 2009 Deutsche Telekom reported huge write-downs on its UK operations, that swung it to a net loss for the first-quarter.<br /><br />The Vodafone interest comes after chief executive Vittorio Colao in November outlined plans to lead consolidation across global mobile telephone markets.<br /><br />He last month won approval from Australian regulators to combine Vodafone&rsquo;s mobile business there with that of rival Hutchison Whampoa.<br /><br />Deutsche Telekom was thought to have rejected an offer for T-Mobile UK from Orange owner France Telecom earlier this month. At the time it was reported the group planned to redouble efforts to boost the unit&rsquo;s profitability.<br /><br />Vodafone, which is headquartered in Newbury, in May revealed a 15.6 per cent boost in revenues to &pound;41bn during the year to the end of March. Colao has been commended for early cost cutting that has allowed the company to perform relatively strongly.<br /><br />Vodafone and T-Mobile declined to confirm the plans when contacted by City A.M. last night. Vodafone shares closed down on Friday at 115.25p.