New Delhi, Dec. 17 -- Tata Consultancy Services Ltd (TCS), India's largest software services company, has won a mega deal valued at more than $1 billion revenues over 10 years from Telefónica UK, the British arm of Spanish telecom giant Telefónica, ending a nearly two-year drought in bagging such large deals.

Telefónica UK runs the O2 brand of mobile phone services in the UK.

Mumbai-based TCS will offer application and infrastructure work as part of this contract, much of which is new work for the company, said two executives privy to the development requesting that they remain unidentified in this story. A formal announcement is expected in the coming weeks.

This is the fourth $1-billion deal, all in the UK, under manag...