March 21 (Reuters) - The following are the top stories in the Financial Times. Reuters has not verified these stories and does not vouch for their accuracy.
* Uber faces legal challenge on paying VAT http://on.ft.com/2nga8Il
* Career spy Jeremy Fleming named head of UK's GCHQ http://on.ft.com/2n1Rxxj
* Vodafone opts to merge India unit amid price war http://on.ft.com/2nXSl5x
* Elliott calls for probe into Arconic vote deal with Oak Hill http://on.ft.com/2mOmsMH
* Google apologises to advertisers for extremist content on YouTube http://on.ft.com/2nCR2wZ
* Uber is facing a new legal challenge in London's high court over its payment of value added tax.
* Jeremy Fleming, the deputy director general of Britain's internal security service, will become the new head of intelligence eavesdropping service GCHQ.
* Britain's Vodafone Group and Idea Cellular agreed on Monday to merge their Indian operations in a $23 billion deal, creating the country's biggest telecoms business after the entry of a new rival sparked a brutal price war.
* Hedge fund Elliott Management Corp, which is in the throes of a proxy battle with Arconic Inc, demanded on Monday an independent review of the company's voting agreement with private equity firm Oak Hill Capital Partners.
* Google apologised on Monday for allowing ads to appear alongside offensive videos on YouTube as more high-profile firms such as Marks & Spencer and HSBC pulled advertising for British markets from Google sites.
(Compiled Kanishka Singh in Bengaluru; Editing by Sandra Maler)